For the first time ever we were able to import this tiny fish in larger numbers. Until now the fish was available only by accidental by-catches. Please read more about this new jewel for nano tanks:
Within the family Lebiasinidae, sixteen scientifically accepted species of the genus Nannostomus are known. Still, in aquatic specialist shops only seven different species are offered: N.beckfordi, N.harrisoni, N.marginatus, N. mortenthaleri, N.trifasciatus, and the two 'head-ups' N.eques and N.unifasciatus. occasionally N. digrammus, N. espei and N. limatus are also available.Until today, one other species, N.britskii, is completely unknown to the aquatic world.
Hardly anything can be said about colouration or appearance in general. All other species are fairly known to aquarists but not available in the shops because there is no demand for them. Every now and then, some specimens of the species N.anduzei FERNANDEZ & WEITZMAN, 1987 come as accidental catches to Europe.It can sometimes be found in catches of the Blue Neon, Paracheirodon simulans.Very often, the fish are ignored due to their smallness: they only reach a maximum length of 1.8 cm! With this maximum length, N.anduzei is the smallest species of the genus. By the way: the genus type is N.beckfordi. The authors FERNANDEZ and WEITZMAN named the pretty dwarftetra in honour of Dr Pablo Anduze who supported their research of the fish world of southern Venezuela in every possible way.The reference specimens of this fairly 'new' species come from a collection of a freshwater lagoon that is about 15 km north of Puerto Ayacucho, in the upper regions of the Rio Orinoco. The water temperature in the lagoon was nearly 30° C, the pH differed from 5.0 to 7.0. A second place where N.anduzei was found is in northern Brazil. Dr WEITZMAN was asked to identify a collection of fish from this particular place; several specimens of N.anduzei were among them.The fish had been collected in the waters of a savanna in the Rio Negro area. These stretches of water belong to the Rio Ererê which comes from the North and flows (about 250 km northwest of the mouth of the Rio Branco) into the Rio Negro, near the Rio Padauari which came to our knowledge through exciting catches of Dwarf cichlids.This particular place is one of the socalled 'black water' regions. Interestingly, the fish caught there have the same colouration as the specimens caught in Venezuela but the males of the Brazilian form have a much longer anal fin. N. anduzei differs from all other Nannostomus species in the lacking of dark spots or bars in night colouration. In night colouration these fish seem to be transparent and display a golden shine while the red in the anal fin and the caudal base is hardly recognizable. The fish that are imported as accidental catches probably come from the Rio Ererê region. For keeping them one needs only a small aquarium with a volume of about 10 to 30 litres. At water parametres of 27° C, pH 7 or slightly below and 10°dH hardness the precious little fish are absolutely unproblematic to keep. For feeding one should use (due to the smallness of the fish) very fine, sieved Cyclops, sometimes small Grindal Worms or artemia nauplia.Occasionally they also enjoy fine dry food. If you keep a swarm of N. anduzei under the conditions mentioned above you will soon observe the first courtship rituals of the males.Now, the dominant males display a blood red caudal fin base and anal fin. The golden horizontal bar shines in a light green and the brown back as well as the brown horizontal band below the gold-green bar turns grey-brown. After this impressive courtship display one of course hopes for numerous offspring of this pretty and rare fish. But although I very often watched courtship rituals the fish never spawned. So I decided to try to breed with a swarm of four males and six females which were all animals that I had picked out from several Blue Neon imports. I set up an 8 litre breeding tank; 2/3 of the bottom were cushioned with Java-moss, the surface was covered by Ceratopteris. The spring water I used had pH 6.3 and 2° dH hardness.The swarm was kept like this for ten days; artemia nauplia were fed daily.The food remains accummulated in the light front part of the tank and were carefully sucked out every two days.Afterwards I filled up the tank with fresh spring water. Three days after I had removed the adults from the breeding tank I could see tiny zygotes that stuck to the panes.This way it was easy to measure them: they were three milimetres long, grey-white in colour and very thin. The head with the clearly visible eye was thicker than the rest of the body. Every two days I carefully added two drops of Liquifry to the tank water. At the beginning of the third week I gave some artemia nauplia into the tank but I could not see whether they were eaten or not. After three weeks I removed all plants from the tank.To my disappointment, there were only six young fish. Still, those six were now 4 mm long and had put on considerable weight.As the plants were removed, I could now watch the fry eating the nauplia. At this stage I dared to suck out some mud and fill up the tank with spring water. For eating food remains I put in several Posthornsnails. Although this very first breeding of N. anduzei was not too successful regarding numbers, it still showed that it is possible to breed the dwarf species in the aquarium. It might be possible that the species is (like many of its relatives) a predator of its own eggs. If this is the case it could be wiser to breed only in pairs. It will surely be possible to improve breeding results so that the pretty species can be part of its owner's life for a long time.
Text & Photos: Dieter Bork
Reprint from AqualogNews No 7, actualized 4/2009
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