Trichomycterus alternatus: In the shadow of the vampire

13. March 2009


Sometimes fishes have the same problems as human beings: one cannot choose his relatives! And so the good reputation of a small fish sometimes is destroyed due to the bad one of a cousin. The most by far feared species of fish in South America is the so-called candiru. In fact, the name candiru is applied to a number of different species in different genera, but this does not matter in our context here. The candiru is able to penetrate the ureter of a human if the person is urinating under water.     This causes horrible infestions that can even be fatal. The fish has spines on the operculum which make it impossible to move backwards. So the candiru dies in the ureter and the victim becomes hazared from inside.


Of course this is not the real intention of the candiru. Its attitude is to find one of the giantic catfishes and suck blood from their gills. When a candiru swims into a human´s ureter this is only an accident. Nevertheless, even being a bloodsucking parasite does not make the candiru more sympathic…..



This is pretty sad for some of the close relatives of the candiru are charming and interesting aquarium inhabitants. One of them is Trichomycterus alternatus from Brazil which we were able to import recently. They reach about 10 cm and remind of loaches with an walrus´ beard. It is very interesting that both the sexual dimophism (males and females are differently coloured; moreover males have longer and broader pectoral fins) and the juvenile coloration is very similar to the stone loach (Barbatula barbatula).



Regarding feeding this loach-cat is completly unproblematic. The species likes the community of its own kind and should always be kept in groups. Otherwise the fish will be shy and hiding. The water temperature can be between 22 and 25°C. No special recommendments for the aquarium water are required,but it should be clean and oxygen rich. As the fish originate from fast running brooks the like a good filter currency.

Text & photos: Frank Schäfer