Author Archives: Frank Schäfer

Since we went online with our homepage over 20 years ago, many new discoveries have been presented here.  Some of them were able to establish themselves as ornamental fish, others disappeared again.The former category includes Hyphessobrycon robustulus, which was initially exported from Peru as “junior tetra”; it is now also regularly bred commercially.The somewhat unusual name comes from the fact that the Peruvian exporter – Jorge Panduro Sr. – handed over the business to his son – Jorge Panduro Jr. – at the time of the discovery of this beautiful tetra. He thought it would be a nice idea to share this with his customers in the form of an interesting novelty. Another popular name for this species is “Panduro tetra” or “Pandurini tetra”, which needs no further explanation after what has been said so far.

Hyphessobrycon robustulus was already described by Cope in 1870 under the name Hemigrammus robustulus. Anatomical features led to its transfer to the genus Hyphessobrycon. The type locality was Pebas in Peru, which at that time belonged to Ecuador. To our knowledge, the “official” assignment of the junior tetra to the species Hyphessobrycon robustulus was made by Zarske in 2007. Previously, another, paler species was listed under this name (e.g. Aquarien-Atlas, Vol. 1, 1990), which was later scientifically described as Hyphessobrycon frankei. 

In general, the name Hyphessobrycon robustulus has become established for the junior tetra. In February 2024 a scientific checklist of all tetra species was published. Here, Hyphessobrycon robustulus is listed as a currently scientifically unclassifiable species (“species inquirendae”), which is only known according to the types from 1870. 

It is therefore not impossible that we will have to retrain at some point. Incidentally, the fishing area for the junior tetra is in the area around Tamishiyacu in the Fernando Lores district of Peru, around 50 km upstream from Iquitos.  

The junior tetra is an ideal aquarium fish, a picture-book tetra. It is small (3.5 – 4 cm), peaceful, colorful and lively. The species makes no special demands on the water composition, the temperature can be between 22 and 28°C. Hyphessobrycon robustulus exhibits an unusually strong sexual dichromatism for characins. All fin parts that are red in the male are yellow in the female.This can be seen particularly well in the video of the species that we have posted on YouTube: https://www.youtube.com/watch?v=JzonUg3cd-s

The pictures for this post show wild-caught specimens that we are once again able to offer.

For our customers: Wild-caught specimens have code 261432, captive-bred specimens code 261423 on our stock list. Please note that we only supply the wholesale trade.

Literature: 

Riehl, R. & Baensch, H. A. (1990): Aquarien Atlas Band 1. 8. Auflage. Mergus Verlag, Melle. page cited: 290

Toledo-Piza, M., E. G. Baena, F. C. P. Dagosta, N. A. Menezes, M. Ândrade, R. C. Benine, V. A. Bertaco, J. L. Birindelli, G. Boden, P. A. Buckup, P. Camelier, F. R. Carvalho, R. M. C. Castro, J. Chuctaya, E. Decru, E. Derijst et al. (2024): Checklist of the species of the Order Characiformes (Teleostei: Ostariophysi). Neotropical Ichthyology v. 22 (no. 1): e230086: 1-548.

Zarske, A. & J. Géry (1997): Hyphessobrycon frankei sp.n. Die Aquarien- und Terrarienzeitschrift DATZ 50 (5) 1997: 308-312 

Zarske, A. (2007): Hyphessobrycon robustulus (Cope, 1870). Aqaristik Fachmagazin, 198: 26-28

Text & photos: Frank Schäfer

The marbled hatchetfish (Carnegiella strigata) is the ideal aquarium fish. It remains small (4 cm), is peaceful, and has interesting coloration. The species is widespread throughout South America (Brazil, Ecuador, Bolivia, Colombia, Guyana, Peru, and Suriname) and is common. That is why it is almost always available in the ornamental fish trade. 

The distinctive shape of the fish and the variability of their markings have led to several, sometimes conflicting, revisions in the past. Furthermore, there were early instances of misidentification and duplicate descriptions. One thing is certain: the Marbled hatchetfish looks different in its various ranges. In the past, several subspecies were therefore described, such as fasciata from Brazil (Tabatinga), marowini and surinamensis from Suriname, and vesca from Guyana. Currently, however, these subspecies are not scientifically recognized. 

Perhaps the most beautiful—because it is the most striking—variant comes to us from the upper Amazon (Peru and Colombia) and is sold in the trade as “vesca.” The difference between this trade-vesca and “normal” strigata—which were at one time even classified as separate species—lies in the pattern. In strigata, as it is known in the trade, the widest body band forks well below an imaginary horizontal line across the belly to the base of the anal fin, whereas in the trade-vesca, it forks well above this imaginary line. As a result, in this „trade-vesca“, this widest of all body bands is very broad, and the fish appears visually much darker than the strigata form. 

The only problem is that the names are used exactly the wrong way around in the trade. Based on Weitzman’s careful research findings, the dark fish is the “true” Carnegiella strigata, while the “true” vesca is the lighter form, in which the widest body band already forks near the edge of the belly. Regardless of all the confusion: here you will find pictures of the “trade-strigata”: https://www.aquariumglaser.de/en/fisharchive/carnegiella-strigata-lg-xlg-2/; all pictures in this post show “trade-vesca.”

Hatchetfishes are somewhat skittish during the acclimation period and should never be kept with aggressive species. They are ideally suited to being kept with bottom-dwelling fish such as armored catfish. When feeding, ensure that the fish only take food from the surface. Flake food provides a good dietary foundation, but for breeding, you’ll need to put in a bit more effort and feed them small insects such as fruit flies. It is important to feed them several times a day in small amounts. The sexes are not easily distinguishable by appearance, but females grow slightly larger and become rounder around the midsection during the spawning season.

For our customers: these fish have code 214301 (sm) to 214306 (lg-xlg) on our stock list. Please note that we supply exclusively to wholesale customers.

Text & photos: Frank Schäfer

The real headstander Anostomus anostomus is one of the most beautiful characins in South America. It looks like the big brother of the three-banded pencil fish, Nannostomus trifasciatus. Anostomus anostomus grows to a length of 15–18 cm. Unfortunately, there are currently hardly any exports of ornamental fish from Guyana, which is why the Anostomus anostomus has become a rare sight in aquariums. 

Now we can finally offer captive-bred specimens of these magnificent fish. At a length of about 3–4 cm, they aren’t quite as beautiful as the adults yet, but they’ll get there. The last wild-caught specimens we were able to import in 2018 were young adults and 9–12 cm long; we’ve included photos of these fish in this post for comparison. 

As the first volume of the Aquarium Atlas so aptly puts it: “Anyone who hasn’t kept this fish isn’t a true aquarist!” There’s nothing more to add to that….

For our customers: the animals are listed on our stock list as wild-caught (currently unavailable!) with codes 205501 (3–4 cm) through 205507 (10–12 cm) and as captive-bred (3–4 cm) with code 205521. Please note that we supply exclusively to wholesalers.

Text & Photos: Frank Schäfer

One of the newest stars in the tetra world is the stunning Inapichthys luizae (for more information, see https://www.aquariumglaser.de/en/fisharchive/inpaichthys-luizae-2/). Previously, we sourced these fish from breeders in East Asia; now they are also available as locally bred stock.

For our customers: these fish are listed under code 264792 on our stock list. Please note that we supply exclusively to wholesale customers.

Text & photo: Frank Schäfer

Alestopetersius smykalai is the only species of Congo tetra in the strict sense that does not originate from the Congo basin, but from the Niger. It only grows to a length of about 5-6 cm, which makes it ideal for owners of smaller aquariums. Due to the magnificent blue back of the males, which differ from the females in their long dorsal fin and completely different shaped and white-edged anal fin, the animal has rightly been given the name “Blue Diamond.” 

These fish are easy to care for. Any tap water suitable for drinking is suitable, and the pH value should be approximately neutral. Water measurements on site often reveal surprisingly cool water temperatures of 21-23°C. The temperature in the aquarium can also be slightly higher, but it should not be excessive. A. smykalai is somewhat skittish and should therefore only be kept with calm and peaceful species; for their part, A. smykalai are completely peaceful. Well-planted aquariums with dark bottoms and not too bright lighting bring out the colors of these fish particularly well. They will eat any standard ornamental fish food of a suitable size, but fruit flies (Drosophila) are a particular treat for all Congo tetras. 

For our customers: depending on their size, the animals have codes 100181 (small) to 100184 (large to extra large) on our stock list. Please note that we only supply wholesale customers. 

Text & photos: Frank Schäfer

Traditionally, two species of red-eyed Moenkhausia are distinguished, which are virtually indistinguishable in appearance. These are M. oligolepis from the Amazon region and the Guianas, and M. sanctaefilomenae from the adjacent southern zone, the Rio Paraguay and Parnahyba. There are color-based details for species differentiation, but these are often unreliable. For example, M. oligolepis is also called the “mirror-spot tetra” because the prominent black spot on the base of the tail—which all species in this group possess—is flanked at the front and back by a broad white band. However, this also applies to some M. sanctaefilomenae. A reliable distinguishing feature is therefore that M. oligolepis has more—and thus smaller—scales than M. sanctaefilomenae. In the longitudinal row, M. oligolepis has 29–32 scales, while M. sanctaefilomenae has 22–26. 

But it would be too simple if there were only these two options. In fact, two additional “red-eyed Moenkhausia” species have been described in recent years: M. forestii (2009) and M. pyrophthalma (1994). M. forestii—just like M. sanctaefilomenae—originates from the Rio Paraguay basin and differs only slightly from M. sanctaefilomenae. We quote: “Moenkhausia forestii can be distinguished from M. sanctaefilomenae in the number of transverse series of scales above the lateral line (5, vs. 4 scales, respectively), by the number of transverse series of scales below the lateral line (4, vs. 3 scales, respectively).” All three red-eyed Moenkhausia are currently classified in the genus Bario. In the hobby, M. forestii has likely not yet appeared, or rather, it is very unlikely that it will be recognized as a species distinct from M. sanctaefilomenae. The fourth species, M. pyrophthalma (the species name means “fire eye”), is currently classified in the genus Ramirezella; this fish is much slimmer than those mentioned so far and has a completely different pattern at the base of the tail, making it virtually impossible to confuse.

The most recent research shows that there are actually three species of red eyed Moenkhausia in the drainage of the Rio Paraguay: B. forestii and B. sanctaefilomenae (both with an incomplete lateral line) and B. australis (with a complete lateral line). The latter was described as early as 1908, but it was later believed that the lateral line was variable and unsuitable for species identification.

We are occasionally able to import wild red-eyed Moenkhausia, sometimes M. sanctaefilomenae from Paraguay (see https://www.aquariumglaser.de/en/09-characoids-tetra-relationship/moenkhausia_sanctaefilomenae_wild_en/) and sometimes M. oligolepis from Peru. 

Caring for and breeding both species is easy (probably also for B. forestii and B. australis, if one could obtain them); water parameters play only a minor role. pH levels between 6 and 8, soft to moderately hard water (and even hard water after acclimation), a water temperature between 22 and 26°C as a guideline (it can occasionally be slightly lower or higher), and red-eyed Moenkhausia will thrive. They will eat any commercially available ornamental fish food of suitable size. Red-eyed Moenkhausia should always be kept in as large a school as possible. With a maximum length of 12 cm (total length including tail fin), M. oligolepis grows significantly larger than M. sanctaefilomenae (approx. 7 cm) and is therefore better suited than the latter as a companion fish for larger cichlids, etc.

For our customers: M. oligolepis has – depending on size – code 268902 (md), 268903 (md-lg), and 268904 (xlg) – on our stock list. Please note that we supply exclusively to wholesalers.

Literature:

Mirande, J.M., Körber, S., Terán, G.E. & G. Aguílera (2024): Welche Spezies mit roten Augen ist es? Die Moenkhausia oligolepis Gruppe in Argentinien (Characiformes: Characidae). AKFS-aktuell (49): 23-30

Text & photos: Frank Schäfer

In southwestern Ecuador, on the Pacific side of the Andes, lives the remarkable tetra Rhoadsia altipinna. In terms of coloration, this species—also known as the rainbow tetra—resembles an XXL version of the brilliant tetra, Moenkhausia pittieri. But when it comes to behavior, one can’t help but think that this tetra originally planned to become a cichlid. The males of R. altipinna, recognizable by the red edge on their anal fin and which also develop much larger fins as they age, occupy spawning territories and defend them vigorously. The males even engage in direct brood care (in this case, cleaning debris from the eggs).

Unfortunately, the species has become rare in aquariums, as there are currently no exports from Ecuador. The last imports were so long ago that we had to dig quite deep into the archives to find a few pictures of larger specimens showing the male’s red anal fin edge; unfortunately, this feature develops quite late.

From time to time, we are able to offer a few 4–6 cm long juveniles of this fascinating and magnificent species. Males can reach an impressive maximum length of 17 cm. Females always remain considerably smaller; the literature cites 9 cm. Regarding water parameters (total hardness up to approx. 15°dH, pH 6.3–7.5, 22–25°C), care and breeding are considered easy; spacious aquariums and nutritious food are particularly important. While they generally accept any type of standard ornamental fish food, coarse frozen and live food (especially insects) should not be missing from their diet, particularly if egg production in the female is desired.

For our customers: these fish have code 287602 on our stock list. Please note that we supply exclusively to wholesalers.

Text & photos: Frank Schäfer

There are few species of tetras that have been depicted under incorrect names in the literature as often as those of the genus Mimagoniates. These attractive fish are occasionally exported from southern Brazil as ornamental fish. Since they reproduce via internal fertilization—meaning the female can lay fertilized, viable eggs some time after fertilization even in the absence of males—they piqued the interest of biologically curious aquarists early on. The fertilization process, in particular, aroused and continues to arouse curiosity. 

But the confusion! We don’t want to overcomplicate things here; anyone wishing to delve deeper into the subject should consult the 2009 revision of this group by Menezes and Weitzman. In any case, the animals originally described by Steindachner in 1877 as Paragoniates microlepis have been referred to in the literature as Coelurichthys iporangae (genus name originally misspelled as “Coalurichthys”), C. microlepis, C. tenuis, C. lateralis, Mimagoniates microlepis, M. tenuis, M. inequalis, M. barberi, and M. lateralis. Some of these species actually exist; they look similar but are simply different species, while others are synonyms. The risk of being led in the wrong direction when studying the literature—and even more so when Googling or using AI—is therefore very high. For us aquarists, the combination of a clearly recognizable shoulder spot and the very broad body band is the best identification criterion.

Mimagoniates microlepis grows to about 6–7 cm in length in the aquarium (total length, including the caudal fin); wild specimens remain about one centimeter smaller. They are very lively schooling fish that prefer to live in streams in the wild but have proven to be adaptable. Most often, cool, shaded clear-water streams serve as their habitat, but the fish are also found in blackwater streams and can even adapt to heavily disturbed habitats where humans have destroyed the original “Mata Atlântica” flora. Mimagoniates microlepis has even been documented in stagnant waters. It is widely distributed: coastal area from southern Bahia to northern Rio Grande do Sul and also in the upper rio Iguaçu and rio Tibagi, upper rio Paraná basin, Brazil

In the hobby, such “tail-gland tetras” have been known since 1907. The males possess a complex glandular apparatus at the base of the caudal fin, constructed from scales, which apparently produces specific sexual attractants (pheromones). The courtship is an incomparable spectacle in which the males perform elaborate swimming maneuvers (“mating dances”) in front of the females. During the actual mating, the male wraps himself around the female like a ring. In the process, a sperm packet is expelled, which the female absorbs. Egg laying often occurs only days, and reportedly sometimes even weeks or months later. The female prefers to attach the spawn to the underside of aquatic plant leaves.

Mimagoniates microlepis is a peaceful species that accepts all standard types of food. It is important that the water temperature does not remain too high for extended periods. Temperatures between 16 and 24°C are appropriate, though 18–20°C should be maintained for most of the year. This species would likely benefit from occasional outdoor rearing, but under such conditions, it is unfortunately difficult to observe the fish.

For our customers: these fish have code 268563 on our stock list. Please note that we supply exclusively to wholesalers.

Literature:

Menezes, N. A. & S. H. Weitzman (2009): Systematics of the neotropical fish subfamily Glandulocaudinae (Teleostei: Characiformes: Characidae). Neotropical Ichthyology v. 7 (no. 3): 295-370

Text & photos: Frank Schäfer

Barracuda tetras of the genus Acestrorhynchus are very well suited for aquarium keeping, even though they are true predatory fish and primarily feed on small fish in the wild. Several species grow to a medium size, about 20–30 cm, but there are also dwarf species, including A. isalinae, which reaches only about 7.5 cm in standard length (i.e., about 10 cm in total length; after all, the caudal fin is usually not included in the measurement for fish); Imported specimens sometimes include giants measuring about 12 cm in total length (ie with caudal fin). This species is also the most attractive Acestrorhynchus in terms of body markings: It has two black longitudinal bands and a partially red or yellow caudal base spot; overall, the caudal base spot is divided into three sections. The top section is red or yellow, the middle section is black, and the bottom section is white.

Acestrorhynchus isalinae was first scientifically described in 1983 from the drainage of the Rio Madeira. No exports of the species originate from there, but there is a beautiful book about the fish of the Rio Madeira; the A. isalinae depicted there matches the animals we regularly import from Peru in all color characteristics. As early as 1909, Eigenmann described an extremely similar species from British Guiana, namely Acestrorhynchus nasutus. It is occasionally speculated that A. nasutus and A. isalinae are the same species, or that all fish imported as A. isalinae are in fact A. nasutus.

However, as can be clearly seen in the 1903 photograph of the type specimen of A. nasutus, the black caudal base spot in this species is not punctate as in A. isalinae, but rather diamond-shaped, extending to the end of the caudal fin; Furthermore, in A. nasutus, the ventral stripe ends above the anal fin, whereas in A. isalinae it extends along the entire length of the abdomen. Apparently, A. nasutus has never been imported for the aquarium trade. A. nasutus also grows to only about 7.5 cm in length. Furthermore, the similarly colored A. maculipinna from the Amazon region in Brazil—which also remains small (8 cm without the caudal fin)—has a large black spot at the base of the dorsal fin.

Acestrorhynchus are generally relatively peaceful toward one another and toward other fish that are not potential food sources. However, this must be modified in that it is not advisable to keep specimens of different sizes together in the case of A. isalinae. In this scenario, the larger specimens will bully the smaller ones, even if the size difference is only 1–2 cm. In extreme cases, the bullying can even be fatal, so exercise caution!

The chemical composition of the water is relatively unimportant for A. isalinae; a pH between 6 and 8, water hardness ranging from soft to moderately hard, and a temperature between 22 and 26°C are ideal conditions. Feeding presents a challenge. Live feed fish should be avoided whenever possible, as they can always carry pathogens. Smaller A. isalinae readily eat live white mosquito larvae, for example. With a little patience, the animals can almost always be accustomed to coarse frozen food.

For our customers: the animals have – depending on size – code 202100 (4-5 cm) to code 202104 (9-12 cm) on our stock list. Please note that we supply exclusively to wholesalers.

Literature:

Eigenmann, C. H. (1912): The freshwater fishes of British Guiana, including a study of the ecological grouping of species, and the relation of the fauna of the plateau to that of the lowlands. Memoirs of the Carnegie Museum v. 5 (no. 1): i-xxii + 1-578, Pls. 1-103.

Menezes, N. A. & J. Géry (1983): Seven new acestrorhynchin characid species (Osteichthyes, Ostariophysi, Characiformes) with comments on the systematics of the group. Revue Suisse de Zoologie v. 90 (no. 3): 563-592.

de Queiroz, L. J., Torrente-Vilara, G., Ohara, W. M., da Silva Pires, T. H., Zuanon, J & C. R. da Costa Doria (2013): Peixes do Rio Madeira, Vol 1-3, Sao Paulo

Text & photos: Frank Schäfer

New imports often pose a significant challenge when it comes to identification. A good example of this is the beautiful tetra from Peru, which we were recently able to import again after exactly 25 years, but whose identity remains highly questionable. At the time, based on the available data, we identified the fish as Acrobrycon ipanquianus, an identification that cannot be upheld in light of recent research findings on A. ipanquianus.

At first glance, the small (approx. 3 cm) fish strongly resembles the Blue Peruvian tetra, Knodus borki. At second glance, however, it differs significantly from that species due to its cherry-red adipose fin. The characteristic of a red adipose fin is extremely unusual in characins in general and is displayed by all specimens of the new imports regardless of their mood, making it a species-specific trait in living animals. Unfortunately, red and yellow colors fade very quickly in preserved fish. In scientific species descriptions, such a characteristic is therefore only mentioned if the live coloration is known. However, this is very rarely the case.

The genus Knodus, together with its immediate sister genus Bryconamericus, forms a large species complex. According to Fishbase (accessed on March 18, 2026), 81 species are currently assigned to the genus Bryconamericus, and 29 species to Knodus. There is some overlap between the two. The only difference between Bryconamericus and Knodus is that in Knodus, parts of the caudal fin are scaled, whereas in Bryconamericus they are not. However, there are Bryconamericus species that have a few large scales at the junction between the trunk and the caudal fin. For this reason, some ichthyologists view Knodus merely as a synonym for Bryconamericus. This makes evaluating the literature difficult. There are hardly any live photos of any of the 110 species. Our new import has—clearly visible in some of our photos—quite dense scaling on the proximal part of the lower caudal fin lobe. It is therefore most likely a Knodus, but there is currently no way to definitively identify our new imports.

At the moment, everything points to Knodus sp. “Red Adipose Fin” being either an undescribed species or a member of another characin genus that we are not currently aware of. Even though this is somewhat unsatisfying given the considerable effort we have already put into attempting an identification, we should therefore leave it at the provisional designation Knodus sp. “Red Adipose Fin” for the time being.

Watching this lively and beautiful fish is a lot of fun. It has a remarkable ability to change color. It lacks a humeral spot entirely. Instead, it has a black longitudinal band that runs along the center of the body, starting at the edge of the gill cover and ending at the tip of the caudal fin. The pigment cells containing the dark pigment that form the longitudinal band can be contracted so strongly by the living fish that it appears completely transparent from one moment to the next. The coloration features a beautifully blue-iridescent back and a red adipose fin. Additionally, the anal fin may turn red, and occasionally a red spot appears at the base of the caudal fin. In terms of care, the new Knodus sp. “Red Adipose Fin” proved to be completely trouble-free; they eat all standard foods and show obvious well-being in soft to moderately hard water at 22–26°C.

For our customers: the animals have code 264748 on our stock list. Please note that we supply exclusively to wholesalers.

Text & photos: Frank Schäfer

Anyone who has ever dealt with piranhas and their species identification knows that it is difficult! Piranhas change their coloration significantly over the course of their lives, and in many cases, this coloration also varies individually. The body shape is also subject to ontogenetic changes (ontogenesis: individual development, as opposed to phylogenesis, the phylogenetic, genetically determined development). That is why the history of research on piranhas is full of errors. This applies both to scientific research and, to an even greater extent, to aquarium research. Every new publication brings new insights. And it seems that the description of a new piranha species (Serrasalmus magallanesi) from the upper Rio Madeira system in Bolivia has brought with it the clarification of an old error.

Serrasalmus hollandi is a well-known species that was first described in 1915 from the Rio Guaporé near the city of Maciél in Brazil. The Rio Guaporé is known to be the border river between Brazil and Bolivia (where it is called Rio Iténez), so the first describers also had to redefine S. hollandi in order to distinguish their new species from the well-known one. 

In aquariums, several piranha species have been identified as S. hollandi: erroneously, it seems. The “real” S. hollandi is a blunt-snouted piranha that is extremely similar to S. humeralis, S. eigenmanni, and S. serrulatus, and some age classes of S. gouldingi also look very similar. Based on the latest findings, it can be assumed that all piranhas from Peru previously referred to as “S. eigenmanni” are actually S. hollandi. S. eigenmanni is only found in Guyana.

Serrasalmus hollandi reaches a body length of around 20 cm. The species is considered a specialized fin eater, which means it is difficult to keep in groups, as even conspecifics are generally regarded as a food source. Since such piranhas are only kept by specialists and research institutions, further information on keeping them in aquariums is unnecessary at this point.

For our customers: S. hollandi has code 292200 (2-3 cm) to 292205 (12-15 cm) on our stock list. Animals currently imported from Peru are listed under “cf. hollandi” with the code numbers 292212 (4-6 cm) and 292213 (7-10 cm). Please note that we only supply wholesale customers.

Literature:

Gallo-Cardozo, F., M. Maldonado, M. Careaga & F. M. Carvajal-Vallejos (2024): A new species of Piranha (Serrasalmus, Serrasalmidae) from the upper Madeira River system, Amazon basin, Bolivia. Journal of Ichthyology v. 64 (no. 3): 386-409

Text & photos: Frank Schäfer

The tetras belonging to the genus Pyrrhulina combine the advantages of two basic groups of ornamental fish. The first group are the schooling species that are always visible and swim merely in the open water: tetras and barbs. The second group has a faszinating behaviour and takes care for the brood: the cichlids and the labyrinth fish. 

One of the most beautiful Pyrrhulia species is P. spilota, which we are able to import from Peru from time to time. P. spilota usually swim around in open water, as is typical for tetras. They prefer the upper third of the water column, but can be found everywhere. They eat all types of fish food, including dry food, and leave the plants untouched. In this respect, their behavior is largely similar to that of other tetras.

When the animals enter breeding season, everything changes. During this time, the males develop fantastic colors and occupy territories, preferably near a broad-leaved plant, or, if necessary, near a stone or root. This is where the fish lay their eggs. Unlike other tetras, which scatter their eggs indiscriminately, Pyrrhulina produce a compact clutch that is very similar to a cichlid clutch. At this time, there is no male that does not have slightly damaged fins from fights with other males. This is part of the process, completely normal and harmless. Once the spawning season is over, everything grows back.

As with labyrinth fish, the male takes care of the brood. And he takes his task very seriously! Any tank mates would be well advised not to get too close to the clutch. Once the young hatch, the brood care instinct disappears and Pyrrhulina return to being normal, beautiful tetras…

For our customers: P. spilota has code 286782 to 286785 on our stock list, depending on size; the fish are usually sent to us in mixed sizes. Please note that we only supply wholesale customers. 

Text & photos: Frank Schäfer

The classification of the genus of African alestid characins is the subject of ongoing debate, with no end in sight. There is constant back and forth, especially with regard to the Congo characins, which are of some importance in aquariums. Just recently, in the latest checklist of characins (Toledo-Piza et al, 2024), P. bleheri, which at first glance is very similar to the “normal” Congo tetra (Phenacogrammus interruptus), was listed in the genus Alestopetersius. There are currently 12 accepted species in Alestopetersius. Many are very similar to each other and difficult to identify. A. smykalai from the Niger is easily recognizable, but the species from the Congo – all the rest – are very tricky. Males in breeding coloration are characterized by their coloring, but it can take several weeks to months for them to get into the mood for breeding. For understandable reasons, we cannot wait that long in the trade.

We recently received a shipment of Congo tetras from the Congo labeled “Alestopetersius brichardi.” This species does exist, and a quick Google image search using this name returned our fish among the results. In the meantime (after 10 days), some of the males have changed color, causing us to have serious doubts. Fortunately, the last revision of all Alestopetersius species was not long ago; it was carried out in 2012 by Mbimbi Mayi Munene & Stiassny on the occasion of the description of a new species. According to this, A. brichardi is a slender fish with a broad black longitudinal band that extends to the end of the caudal fin. A. leopoldianus (https://www.aquariumglaser.de/en/09-characoids-tetra-relationship/alestopetersius-leopoldianus-2/) is very similar. Our fish, on the other hand, has a significantly higher back, the longitudinal band (which is only visible in certain lighting conditions) is much narrower, and there is a vertical humeral spot on the shoulder, which is absent in A. brichardi.

We have decided to leave our new import without a “proper” name and instead name it after the location where it was found. According to the supplier, these animals were caught in the Kwilu River, one of the larger tributaries of the Kasai River, not far from the city of Bandundu in the province of the same name in the DR Congo. In a scientific collection published in 2011 (Mbimbi Mayi Munene & Stiassny, 2011), two Alestopetersius species from the Kwilu are reported: the newly described A. conspectus (this species differs from all other A. species in, among other things, a striking flag pattern on the caudal fin) and A. sp. “mbuji”; unfortunately, the latter species was only available in one specimen that was not described in detail, but DNA analysis showed that it is a new species not yet recorded scientifically. Of the species described, the similarity to A. bifasciatus seems greatest to us due to the high proportion of black coloring in the caudal fin.

Such novelties are relatively expensive for several reasons, and debates about who is right in determining and naming them are counterproductive for the spread of the animals in the hobby, as there is always the underlying suspicion that someone in the commercial chain of catcher-buyer-exporter-importer-wholesaler-retailer has fraudulent intentions. Without a doubt, the newly imported Alestopetersius sp. “Kwilu-Bandundu” are beautiful fish. We can only advise anyone interested in African characins to grab them while they can, as it is highly uncertain when and if another import of these fish will be successful.

Our specimens have proven to be robust and healthy so far. The alpha male photographed (recognizable by the white fin edges) is approx. 5.5 cm long (including tail fin), so Alestopetersius sp. “Kwilu-Bandundu” seems to remain relatively small (although the animals will probably grow another one to two centimeters). They adapt well to life in an aquarium. From experience with other Congo tetras, we know that only soft, slightly acidic water is required for breeding. The only Alestopetersius firmly established in the hobby is the yellow Congo tetra (A. caudalis), which is now almost exclusively offered as a captive-bred species. For more information on this species, see: https://www.aquariumglaser.de/en/fisharchive/alestopetersius-caudalis-4/.

The new Alestopetersius sp. “Kwilu-Bandundu” is completely peaceful. It should be kept in as large a group of conspecifics as possible in a densely planted aquarium that also provides enough swimming space, with lighting that is not too bright. Any drinking water is suitable for keeping them. However, experience has shown that Alestopetersius develop their fins most beautifully in soft, slightly acidic water (pH around 6). The temperature should be between 22 and 28°C. They will eat any food of animal origin, whether dry, frozen, or live. The animals particularly enjoy being fed small fruit flies (Drosophila), a trick used by breeders to achieve the most abundant spawning possible in female A. caudalis.

For our customers: Alestopetersius sp. “Kwilu-Bandundu” has code 100193 on our stock list. Please note that we only supply wholesale customers.

Literature:

Boden. G. in Toledo-Piza, M., E. G. Baena, F. C. P. Dagosta, N. A. Menezes, M. Ândrade, R. C. Benine, V. A. Bertaco, J. L. Birindelli, G. Boden, P. A. Buckup, P. Camelier, F. R. Carvalho, R. M. C. Castro, J. Chuctaya, E. Decru, E. Derijst et al. (2024): Checklist of the species of the Order Characiformes (Teleostei: Ostariophysi). Neotropical Ichthyology v. 22 (no. 1): e230086: 1-548.

Mbimbi Mayi Munene, J. J. & M. L. J. Stiassny (2011): Fishes of the Kwilu River (Kasai basin, central Africa): A list of species collected in the vicinity of Kikwit, Bandundu Province, Democratic Republic of Congo. Check List 7 (5): 691-699

Mbimbi Mayi Munene, J. J. & M. L. J. Stiassny (2012): A new Alestopetersius (Characiformes: Alestidae) from the Kwilu River (Kasai basin) of central Africa; with a phylogeny for the genus and synonymy of Duboisialestes. Zootaxa No. 3166: 59-68.

Poll, M. (1967): Révision des Characidae nains Africans. Annales, Musée Royal de l’Afrique Centrale, Tervuren, Série in 8o, Sciences Zoologiques No. 162: 1-158.

Text & photos: Frank Schäfer

In 2008, while examining a newly imported species (previously referred to by us as Boehlkea sp. “Sky Blue”), Dr. Axel Zarske discovered that it was actually Boehlkea fredcochui. The fish that had been referred to as B. fredcochui for decades, on the other hand, represented a species of the genus Knodus that had not yet been scientifically recorded and was described as Knodus borki in honor of Dieter Bork.

The common name Blue Peru Tetra has remained. The animals were first imported around 1956. The location “Leticia” (Colombia) referred to at the time was the city from which the export took place. To this day, Leticia, located in the border triangle of Peru, Brazil, and Colombia, is one of the most important trading centers for ornamental fish in the Amazon region. Many rarities are even shipped exclusively via Leticia, even though they come from relatively distant areas, simply because Leticia has the infrastructure that makes it possible to market the animals. In fact, Knodus borki occurs in the vicinity of Iquitos. In the hobby, the blue Peru tetra is part of the standard range. It is available all year round, mostly as a captive-bred specimen, but occasionally also as a wild catch. There is also an albino breed.

Knodus borki grows to a length of 4-5 cm (total length, including tail fin) and is a very peaceful, highly active schooling fish. Plants and any other inhabitants of the aquarium are not disturbed. These lively animals are easy to care for. They should be kept in groups of at least 10. Their somewhat “hanging” swimming style is typical of the species. It is not as extreme as that of the Penguin tetras, but it is particularly noticeable when the fish pause briefly (and the photographer can focus and take a picture). Any tap water suitable for drinking is suitable for keeping these fish, and the water temperature can be between 22 and 26°C. They will eat any commercially available ornamental fish food of a suitable size. Males and females differ only slightly in color, but the light areas at the tips of the tail fin are more pronounced in males. They are open spawners without brood care.

For our customers: depending on size, the animal has code 210001 to 210004 (wild catch) and 210011 to 210014 (captive bred) on our stock list. The “real” Boehlkea fredcochui, which is very rarely found in the trade, has code 210051 to 210053. Please note that we only supply wholesale customers.

Text & photos: Frank Schäfer

Since 2018, a relatively small species of tetra from the central Congo Basin has been causing quite a stir: Phenacogrammus sp. “Fantastique.” However, very little literature has been published on these animals to date, which is somewhat surprising given their small size (for an African alestid) and the beautiful coloration of the males, at least at certain times. To our knowledge, these animals have not yet been scientifically studied. Even their classification in the genus Phenacogrammus is questionable, as the generic classification of African small tetras has always been the subject of controversial debate among ichthyologists. 

The externally recognizable species-specific characteristics of Phenacogrammus sp. “Fantastique” are—apart from the magnificent coloring of males during courtship, which they only display after a long period of acclimatization—a slender build, a clearly pronounced shoulder spot ( = humeral spot), black-colored middle rays of the caudal fin in males, in large males these black-colored middle caudal fin rays protrude beyond the rear edge of the caudal fin in the form of a thread-like extension, and, as an important, albeit inconspicuous feature at first glance, a clearly visible white spot on the adipose fin. Taking all these characteristics and the origin (central Congo Basin) together and assuming that this is a species that has already been scientifically recorded, there is much to suggest that Phenacogrammus sp. “Fantastique” is identical to P. deheyni. Just recently (2021), two similar Congo tetras from the central Congo Basin were newly described, namely Phenacogrammus flexus and P. concolor. In the course of distinguishing these two new species from the already known species, the four other species known from the central Congo Basin (P. polli, P. deheyni, P. aurantiacus, and P. interruptus) were also reviewed; Based on this work, it can be ruled out that Phenacogrammus sp. “Fantastique” is identical to any species other than P. deheyni and P. concolor. Unfortunately, the live coloration of P. concolor is unknown. Therefore, it is better to stick with Phenacogrammus sp. “Fantastique” as the name for aquarium imports for the time being.

Due to the complex political situation in Congo and major logistical problems there, Phenacogrammus sp. “Fantastique” is a very rarely imported fish that is also expensive. Like so many Alestidae, the species is also sensitive to transport. Any transfer should be carefully considered. The animals always take quite a long time to acclimatize and are naturally susceptible to disease during this period. The location where it was found is described as follows: a cola-colored, shallow forest stream that flows into the Likouala. Very soft, acidic water (pH 4.5, conductivity 15 µS/cm), water temperature around 24°C at 11.30 in February (dry season), light sandy bottom, wood deposits and dead leaves, no underwater plants. During the dry season, the animals swim in schools of 30-50 specimens (Numrich, 2018).

According to information on the internet, which we cannot verify, the maximum length of Phenacogrammus sp. “Fantastique” is said to be around 8 cm (this probably refers to the total length, i.e. including the tail fin), while Numrich (2018) gives a length of 6 cm. The maximum length of P. deheyni is given as almost 10 cm in aquarium literature, but the adult specimens described in scientific literature were only 5-6 cm long (including the tail fin), and both P. flexus and P. concolor have a standard length (without tail fin) of less than 5 cm. The animals photographed for this post are about 5 cm long, including the tail fin, and have just reached sexual maturity. “Fantastique” is therefore a small fish.

Unfortunately, we have not yet been able to observe the bright red coloration that the males display during the mating season. But this is well known in tetras, just think of Hemigrammus coeruleus (https://www.aquariumglaser.de/en/09-characoids-tetra-relationship/hemigrammus-coeruleus-4/). In their normal coloration, males appear orange-copper with reddish fins and two deep red spots on the caudal fin; females are more plainly colored. In terms of social behavior, feeding habits, etc., we have not yet noticed any differences from the well-known Congo tetra (P. interruptus). We therefore refer you to the extensive literature on this fish.

All in all, Phenacogrammus sp. “Fantastique” is an exciting new addition that we hope will become widely distributed!

For our customers: the animals have code 159102 on our stock list. Please note that we only supply wholesale customers.

Literature:

Numrich, R. (2018): Kongosalmler aus dem Herzen Afrikas. Amazonas Heft 75 (14) 1: 20-27

Poll, M. (1945): Descriptions de Mormyridae et de Characidae nouveaux du Congo belge avec une étude du genre Stomatorhinus et des genres de Characidae nains africains. Revue de Zoologie et de Botanique Africaines v. 39 (no. 1): 36-77

Stiassny, M. L. J., Alter, S. E., Monsembula Iyaba, R. J. C. and T. L. D. Liyandja (2021): Two new Phenacogrammus (Characoidei; Alestidae) from the Ndzaa River (Mfimi-Lukenie basin) of Central Africa, Democratic Republic of Congo. American Museum Novitates No. 3980: 1-22

Text & photos: Frank Schäfer

In 1992, W. L. Fink and A. Machado-Allison described two piranha species of the genus Pristobrycon from locations in the Rio Atabapo basin (Venezuela): P. careospinus and P. maculipinnis. The two species differ in color. While P. maculipinnis has small dots on its body and spots on its vertical fins, the fins of P. careospinus are unmarked and the spots on its body are large. Unfortunately, the scientists only had a few specimens at their disposal. They had six specimens of P. maculipinnis and only one of P. careospinus. This is naturally problematic given the well-known color variability of piranhas and the equally notorious color changes these fish undergo during their growth (scientifically known as ontogenetic color change). 

In 2006, piranhas from Venezuela with very impressive colors appeared on the ornamental fish market for the first time. At that time, they were identified as Pristobrycon maculipinnis, and it was considered likely that P. maculipinnis and P. careospinus were the same species.

We have finally succeeded in importing these beautiful piranhas again, this time four specimens. We now consider the Pristobrycon imported in 2006 and those recently reintroduced to belong to the species P. careospinus and believe that the earlier assumption that P. careospinus and P. maculipinnis were identical was incorrect.

The difference between Pristobrycon and other piranha genera is not visible externally. It is a bone feature, namely the palate (referred to in scientific publications as the palatine or ectopterygoid). This is toothed in typical Serrasalmus species, smooth and toothless in Pygocentrus species, and rough and toothless in Pristobrycon species. Recent molecular biological studies no longer classify P. careospinus in the genus Pristobrycon, but rather in Serrasalmus. The species may therefore be called Serrasalmus careospinus.

Virtually nothing is known about the behavior of this species. In nature, it apparently occurs mostly singly. In aquariums, piranhas are often notorious fin biters, which can make it necessary to keep them singly. On the other hand, Oliver Lucanus (verbal communication) kept a group of the beautiful species we are presenting here, under the name of P. maculipinnis, together for at least a while. Overall, representatives of the genus Pristobrycon (in the conventional sense) are only very rarely kept in aquariums, which is a pity, as all species usually remain under 20 cm in total length and some are very attractively colored. Detailed care reports are lacking in the aquarium literature, not to mention breeding reports. 

The pictures show specimens from the 2006 import and a collage of the four animals that have just arrived in our fishhouse, which naturally still need to recover from the stresses of transport, but are obviously in perfect health.

For our customers: the animals have code 283285 on our stock list. Please note that we only supply wholesale.

Text: Frank Schäfer, photos: Frank Schäfer & Erwin Schraml

The three-banded flag tetra, Hyphessobrycon heterorhabdus, was once one of the most sought-after small tetras. When tetras were very fashionable – in the 1950s to 1970s – this species was classified as a “problem fish” because it did not reproduce without tricks and gimmicks. However, keeping this species without breeding intentions was completely problem-free. Today, we know of a whole complex of three-banded flag tetra species, and identifying them is anything but easy. It is likely that the animals kept at that time were not H. heterorhabdus at all. More information on this can be found here: https://www.aquariumglaser.de/en/09-characoids-tetra-relationship/hyphessobrycon-heterorhabdus-2/

However, a very closely related species of this three-banded flag tetra is fairly easy to identify: Hyphessobrycon amapaensis, the Amapa three-banded flag tetra. This species was caught and brought back from Brazil during an ornamental fish expedition by Bitter and Hessfeld, which was still legally possible at the time (1997). A year later, it was scientifically described as a new species by Zarske and Gery. It was found in a savanna stream on the B156 in the state of Amapa. The water there was clear, slightly brownish, slightly acidic (pH 5.8 to 6.3), very soft (both KH and GH below 1° dH, conductivity 9-13 µS/cm) and around 25-27°C warm. The most interesting accompanying fish was Hyphessobrycon takasei (https://www.aquariumglaser.de/en/09-characoids-tetra-relationship/hyphessobrycon-takasei-2/).

The distinguishing feature of Hyphessobrycon amapaensis is the black section of the longitudinal stripe. In all three-striped flag tetras in the narrower sense, the longitudinal stripe consists of three differently colored, parallel stripes: one red, one light, and one black. In contrast to all other three-banded flag tetras, the black band of Hyphessobrycon amapaensis is greatly widened immediately behind the gill cover to the end of the pectoral fins and also extends into the caudal fin. The uppermost band is coral red and much clearer than in other three-banded flag tetras. To identify the species with certainty, you need to take your time. Depending on its mood, each fish can strongly contract the body cells that contain the black pigment – then the fish becomes light in color and the black markings almost invisible – or expand them. This is what makes the very rapid color change that so many fish exhibit possible. When Hyphessobrycon amapaensis is frightened, the black longitudinal band is often not easily recognizable.

Hyphessobrycon amapaensis is the only species of all three-banded flag tetras to have gained a firm place in the hobby. It is available in good quality as offspring in various sizes almost all year round, although its breeding still requires an experienced tetra breeder even today. Wild-caught specimens only come onto the market very sporadically. The pictures show captive-bred specimens in the md-lg size class. It is an ideal fish for well-maintained community aquariums. Soft, slightly acidic water is favorable for optimal coloration, but the fish are highly adaptable and practically any tap water is suitable for their care. The species is completely peaceful towards conspecifics and non-conspecific fish, and should be kept in a school. The maximum length is about 4 cm. They eat any commercially available ornamental fish food of a suitable size.

For our customers: depending on size and origin, the animals have the codes 259452 (breeding sm-md), 259453 (breeding md-lg), 259454 (breeding lg), 259463 (wild lg), and 259464 (wild xlg) on our stock list. Please note that we only supply wholesale customers.

Text & photos: Frank Schäfer

A pretty new tetra is Inpaichthys luizae, a species that was only formally described in January 2025. It occurs in areas that are hardly accessible to scientists and commercial fishermen because they are privately owned. What is known, however, is that these locations are tributaries of the Rio dos Peixes in Brazil, which in turn is a tributary of the Rio Juruena. The entire area belongs to the Rio Tapajós basin.

This fish first became known in the hobby at the end of 2023. At that time, it was referred to as Inpaichthys sp. “Black Arrow”. As with many new species, only a few specimens initially came onto the market at comparatively high prices; low three-digit euro amounts per specimen were demanded. However, it quickly became apparent that this species is just as productive and easy to breed as its well-known cousin Inpaichthys kerri, the royal tetra. At present (January 2026), the fish are still not cheap, but they are not unaffordable either. We source them as offspring from East Asia.

The sexes of these cute animals, which according to scientific descriptions reach a standard length of about 4 cm (i.e., without the tail fin), are quite easy to distinguish due to the stronger red coloration of the fins in males. This color is already clearly visible in adolescent animals. It can be assumed that aquarium specimens grow 1-2 cm larger than wild-caught fish, a phenomenon that can be attributed to the much better food supply for aquarium fish and, of course, the considerably higher age that fish in aquariums reach compared to wild specimens.

So far, the animals have proven to be absolutely typical small tetras, which do not differ from the royal tetra, Inpaichthys kerri, in terms of aquarium requirements. A very interesting phenomenon with I. luizae is the fact that most specimens have an adipose fin, but some do not. The absence of an adipose fin is very unusual in tetras; at the time, the presence of an adipose fin was one of the reasons for establishing the genus Inpaichthys, as otherwise it is very similar to the genus Nematobrycon (emperor tetras). All Nematobrycon species, without exception, lack the adipose fin. However, there are also specimens of I. luizae without adipose fins, but they are in the minority.

For our customers: the animals have code 264792 on our stock list. Please note that we only supply wholesale customers.

Text & photos: Frank Schäfer

In 2002, a deep red dwarf pencil fish from Peru was imported under the names Nannostomus marginatus “Purple” or N. marginatus “Red.” Axel Zarske from the Senckenberg Natural History Collections Dresden, Museum of Zoology formally described this species in 2009 as Nannostomus rubrocaudatus. We had imported the type specimens on which the scientific description is based from Peru.

At first glance, the new species resembles the already known N. mortenthaleri (see https://www.aquariumglaser.de/en/fisharchive/nannostomus-mortenthaleri-2/), but can still be easily distinguished from this species. N. mortenthaleri, for example, always has a white belly. Further species characteristics are listed in the scientific description. The scientific first description is available as a free download at https://www.senckenberg.de/wp-content/uploads/2019/08/02_vertebrate_zoology_59-1_zarske.pdf.

Nannostomus rubrocaudatus does not exhibit very distinct sexual differences. The intensity of the red coloration varies greatly depending on mood. However, females never turn as red as males. What is particularly tricky is that males low in the hierarchy can fade significantly and camouflage themselves as females in terms of color; females can only be reliably identified by their differently shaped anal fins.

The maximum size of this species is around 3-3.5 cm. It is easy to care for, but should not be kept in small aquariums, as the males fight their rivals quite fiercely and the weaker specimen needs space to escape. If this is not available, damage may occur.

The natural range is in Peru, Dep. Loreto. Here, the species is collected for export near the village of Saramirisa on the Maranon (the upper Amazon) between the tributaries Rio Morona and Rio Santiago. The relatively high price of the fish is explained by the fact that the animals live among dense branches in the wild and have to be laboriously picked out individually. Mass catches, as with other Nannostomus species, where thousands of specimens can easily be caught with a net, are not possible with N. rubrocaudatus.

For our customers: Nannostomus rubrocaudatus has – depending on size – code 272261 (sm) to 272265 (lg-xlg) for wild-caught specimens and 272272 for captive-bred specimens on our stock list. Please note that we only supply wholesale customers.

Text & photos: Frank Schäfer

So-called gold tetras are found in many species of characins in South America. Usually, only a few fish in a school are affected by the phenomenon in which guanine, the substance responsible for the shiny silver or gold glitter effect of the fish scales, is secreted at a much higher rate than usual. We explain this in detail here: https://www.aquariumglaser.de/en/fisharchive/hyphessobrycon-saizi-hyphessobrycon-eos-colombian-gold-tetra/) For the reasons described, the golden sheen cannot be fixed in breeding strains. The offspring of all gold tetras look like the regular form.

However, it is precisely in a tetra, in which wild-caught gold tetras are almost never found, that the genetic fixation of the golden sheen has been achieved. Breeders call this attractive silver-shining fish “diamond,” but it is usually referred to as “platinum” in the trade. The precious metal sheen of this rummynose tetra – technically speaking, Petitella bleheri – is due to a random genetic mutation, not parasite infestation. For information on distinguishing between the three rummynose tetras and general care instructions, see https://www.aquariumglaser.de/en/fisharchive/petitella-rummynose-tetras/

For our customers: you can find the animals on our stock list as “Hemigrammus rhodostomus Platinum” with the code numbers 257362 (md) and 257363 (md-lg). Please note that we only supply wholesale customers.

Text & photos: Frank Schäfer

Nannostomus mortenthaleri from Peru (Rio Nany tributary in the province of Loreto) was the most beautiful new discovery in aquatics in 2000. The close relative of the dwarf pencil, N. marginatus, remains small – approx. 4 cm – and is breathtakingly beautiful in color in the male sex. At least sometimes. Because apart from anatomical details, N. mortenthaleri exhibits behavior that clearly differs from most Nannostomus species. Among conspecifics, N. mortenthaleri forms a distinct hierarchy or pecking order.

Dominant males display an intense red color between the dark longitudinal bands. Lower-ranking males fade and take on the coloration of females. Conversely, dominant females can develop a significant amount of red. N. mortenthaleri‘s behavior is therefore more similar to that of a small Malawi cichlid (Mbuna) than to that of an pencil fish. It is therefore essential to keep this species in a larger group, as otherwise, just like with Mbunas, a tyrant may develop that oppresses all conspecifics so severely that it can even lead to deaths. The gender composition is irrelevant for keeping them in a community aquarium.

In all pencil fish, the shape of the anal fin has proven to be the most reliable sexual characteristic. Unfortunately, the differences are very slight in N. mortenthaleri. The anal fin of adult males is always slightly convex at the front edge, whereas in females it is straight. In addition, females lack the light stripe at the base of the dorsal fin. However, the most reliable way to distinguish between the sexes is by their behavior. We recommend purchasing a group of 10-20 specimens, which should be kept in a larger, heavily structured aquarium (with lots of roots and dense planting). The fish will certainly spawn here (they are open spawners over fine-leaved plants). Although there is hardly any offspring in community tanks, as the adult fish are very cannibalistic, at least you know whether there are really females in the group and can catch them specifically for breeding.

N. mortenthaleri are relatively easy to care for. They adapt well to different water parameters, although soft and slightly acidic water best corresponds to their natural conditions. The water temperature can be between 22 and 28°C. They will eat any standard ornamental fish food of a suitable size. N. mortenthaleri are usually peaceful towards other fish species, but caution should be exercised with closely related Nannostomus species with a similar body shape and coloration.

For our customers: N. mortenthaleri has code 272253 (md) – 272257 (xlg), depending on size. Offspring have code 272259 on our stock list.

Text & photos: Frank Schäfer