There is a silver-white breeding form of Dermogenys siamensis (in the hobby usually called D. pusillus or D. pusilla, but this is a different species, which is not kept in the aquarium), in which – similar to the gold tetras – shiny color pigment (guanine) is produced in excess in the skin cells. In nature such a mutation can hardly survive, since it is immediately discovered and eaten by the numerous fish-eating animals, but in the aquarium such eye-catchers are naturally particularly desired.
Similar to fighting fish (Betta splendens), these half-beaks used to be bred in Southeast Asia for fish fights, because the males can sometimes be very quarrelsome. If you selectively breed particularly combative specimens of this viviparous fish over generations, you can actually get strains that will fence with each other “on command.” But this form of fish fighting has almost disappeared these days. The animals bred for peaceful aquaristics are well compatible with each other, so much so that we have never managed to photograph two males fighting with each other.
For the wild form of D. siamensis see https://www.aquariumglaser.de/en/19-halfbeaks/dermogenys-siamensis-d-pusilla-2/
For our customers: the animals have code 414212 on our stocklist. Please note that we only supply to wholesalers.
Text & photos: Frank Schäfer