We obtained from Nigeria a species of mormyrid which we haven´t seen for years: Brienomyrus brachyistius. This comparably small species (maximum length reported is 17.cm, usually the fish becomes 10-12 cm long) is a close relative to the species B. niger, which we were also able to import again (see http://www.aquariumglaser.de/en/brienomyrus-niger_de_1152.html).
The intelligent and playful fish are very lively. One looks after them not for their coloration, but for their funny looking behaviour.
We have specimens which are more elongate and larger, these we think are males, and deeper bodied, smaller specimens, which we think are females. Nothing is known about the reproduction biology of the species. The fish feed happily on any type of usual fish food (living, frozen, dried) that fits the mouth.
For our customers: the fish have code 103502 on our stocklist. Please note that we exclusively supply the wholesale trade.
Text & photos: Frank Schäfer
Most often this bizarre mormyrid is kept as a single specimen. This is due to the fact that small groups of this fish most often don´t do well in a long time sight and they can perform mobbing against each other even to death. However, in the wild these up to 30 cm long, but rarely longer than 15 cm found animals form sometimes really large schools. In our facility they are kept in groups of about 50 animals in tanks of 200 x 60 x 60 cm. Here the elephant fish forms schools and shows a schooling behaviour as it is hardly seen in any other fish in the aquarium.
More information on Gnathonemus petersii is provided here: https://www.aquariumglaser.de/en/fish-archives/the_possibly_rarest_fish_in_the_world_lives_in_aquarium_glaser_s_fishhouse_en/
For our customers: the fish have code 133502 (7-10 cm) and 133503 (10-12 cm) on our stocklist. Please note that we exclusively supply the wholesale trade.
Text & photos: Frank Schäfer
We obtain comparatively often this interesting mormyrid from Nigeria. Sadly systematics of Mormyrus are confusing. According to the latest scientific state of the art currently five species of Mormyrus occur in Nigeria, among them M. rume. The shape of the snout is the best feature to distinguish the species. Formerly the fish portayed here was named M. longiristris, but this is obviously another species from Mozambique.
Although there do exist reports of up to 100 cm long Mormyrus rume catches of specimens longer than 30 cm are extremely rare. The size of the species is quite well known, for M. rume is a common food fish in its natural range.
In 2002 Fawole published a paper on the natural history of M. rume in Lekki Lagoon in Nigeria. He collected during the study (december 1999 until november 2000) in monthly catches a total of 225 specimens which were studied for development of the gonads, the size, gut content etc. The largest specimen in his study was 23 cm long, the smallest 13 cm. He found sexually ripe females from 13.5 cm standard length on, the whole year through females with ripe gonads were found so the species obviously reproduces the whole year through. The gut content was a bit astonishing for all specimens contained inter alia plant material.
In the aquarium, mormyrids are usually fed with food for carnivorous fishes, especially bloodworms are a very good food for them.
Nobody will keep Mormyrus rume for its brillant colours. Nevertheless they are are very interesting animals. Like all mormyrids they have a „language“ basing on electric impulses and the brain of Mormyrus is – compared with the body mass – very big. The tank should be heavily furnished and as large as possible. These fish should be kept solitary or in larger groups. Two or three specimens usually are very quarrelsome against each other in a long time sight. Many people who watch Mormyrus rume are reminded on the most popular mammal of the seas, the dolphin. And in fact, if one looks at M. rume from face to face the similarity is astonishing!
For our customers: the animals have code 152005 on our stocklist. Please note that we exclusively supply the wholesale trade.
Fawole, O. O. (2002): Morphometry and diet of Mormyrus rume in the Lekki lagoon, Nigeria. Revista de biología tropical, 50 (2): 689-694