Moenkhausia cosmops

29. November 2010

We were recently able to import a very ununsual tetra from Brazil in limited numbers: Moenkhausia cosmops. This species has been described scientifically only in 2007. It is reported so far from the upper basins of the rivers Rio Paraguai and Rio Tapajos in the State of Mato Grosso, namely Rio Juba, Rio Juruena, Rio Papagaio, and their tributaries.

This species has been considered to be a close relative to the well known species Moenkhausia oligolepis (Glass tetra) and M. sanctaefilomenae (Red eye tetra). Other close relatives are M. cotinho, M. diktyota, M. forestii, and M. pyrophthalma which are of no relevance in the hobby so far. All mentioned species have in common a red iris and a conspicious tail spot. M. cosmops can be distinguished from all these species at the first glimpse by the blue-green iris and the red stripe on the snout.

The unique colour pattern reminds one of the one hand on the marvelous emperor tetras (Nematobrycon) and on the other hand on the cute lipstick barb (Barbus erythromycter) from Asia. However, these similarities do not represent any phylogenetic relationship.

Maximum length reported for Moenkhausia cosmops is about 6 cm. In the beginning the fish are a bit shy. In our facility the fish have proofed so far to be hardy and little demanding. Like in most tetras, feeding is quite unproblematic. The stomach of wild fish contained insects (mainly ants), plant material, and algae. The water temperature should be between 24 and 26°C, soft and slightly acidic water is close to the findings in the natural habitat. The biotopes are described as whitewater biotopes with sandy bottom. Here the fish are found in schools with 50 or more specimens which prefer the backwaters near the vegetation of the banks. They live between dead branches etc.

For our customers: the fish have code 268643 on our stocklist. Please note that we exclusively supply the wholesale trade.

Lexicon: Moenkhausia: dedication name for W. J. Moenkhaus, a friend of Eigenmann. oligolepis: ancient Greek, means “with only few scales”. sanctaefilomenae: refers to the collection site of the type specimens (“lagoon near St. Filomena at the Parnahyba”). cosmops: ancient Greek, means “with decorated face”. cotinho: dedication name for a Major Cotinho, collector of the species and Brazilian attaché of the Thayer expedition. diktyota: ancient Greek, means “with reticulated pattern”. forestii: dedication name for Fausto Foresti, a geneticist. pyrophthalma: ancient Greek, means “with red eye”. Nematobrycon: ancient Greek, means “Brycon with a thread”, which refers to the caudal fin; Brycon is another genus of tetra. Barbus: Latin, means “the bearded one”. erythromycter: ancient Greek, means “with red nose”.

Suggestion of a common name: Lipstick tetra

Text & photos: Frank Schäfer