I think these are a Steatocranus species, but I cannot say more from this photo. They are quite like S. tinanti, which I have kept, but I would need to see the shapes of their heads to confirm this. They are fishes with reduced swim bladders which live in fast-flowing rivers and streams, and I suspect that there may be quite a few species yet to be collected, described and imported.
Thank you very much gentle lemur. With this info I was able to search further and now know it should be the "Ultra Slender" Buffalohead - Steatocranus species Ultra Slender, a still undescribed species from the Congo.
