Chrysichthys, but which one ?

[chalamala]

Hello everybody,
6 months ago, I bought 4 young, 2 inches long, silver Chrysichthys, as "Chrysichthys sp Nigeria".
They now have grown up to 7 inches, but I am sure 2 species are present, as one of them is much darker and as a wider head than the three others :




The three plain coloured fishes could be Chrysichthys auratus, as their flanks shine golden under daylight and they come out Nigeria, here are fotographs of their head :




But the dark one has the wide mouth of a dangerous predator :




Sorry for the quality of the pics, the fishes have just been fished out of their tank, they are in a plastic container and, as I already told, I am a poor aquarium fotographer ! Who can help me with the real name of those fishes ? Thanks !

[Birger]

We need petteri, I think he has the same fish as these ones.

Birger

[jippo]

We need petteri, I think he has the same fish as these ones.

Birger

Sorry but I can't tell exact species, we have to wait until there is a revision for this genus. I have same looking specimens but I can't even tell their species

[chalamala]

But can both fishes belong to the same species (male and female), whatever species it is, despite the differences in colour and shape of the head ?

[naturalart]

Funny, I just saw what I believed to be the same 2 species in a shop. They were both in the same tank and were labeled C. auratus. And I saw the same differences. There were 6 of the golden/olive colored species and this one other fish. Dark/black, about the same size as the others. But it definitely had a different behavior/energy. It didn't hang out with the other fish, and its eyes bulged out above the top line of the head. Closest I could find in the cat-elog is http://www.planetcatfish.com/common/spe ... es_id=2121 That said, I am no expert on this group of catfishes.

[chalamala]

Funny, I just saw what I believed to be the same 2 species in a shop. They were both in the same tank and were labeled C. auratus. And I saw the same differences. There were 6 of the golden/olive colored species and this one other fish. Dark/black, about the same size as the others. But it definitely had a different behavior/energy. It didn't hang out with the other fish, and its eyes bulged out above the top line of the head. Closest I could find in the cat-elog is http://www.planetcatfish.com/common/spe ... es_id=2121 That said, I am no expert on this group of catfishes.

I experienced just the same, Naturalart : my dark fish differs from the others not only by its appearance, but also by its behavior/energy ! But often males are more boisterous than females, so I'm still not sure I have one species or two... Anyway thanks for sharing your experience!

[wayne the pain]

From what i can see and from what i remember of a fish i owned years ago it looks like it could be C brachynema, or it certainly looks closest to it.

http://www.planetcatfish.com/common/spe ... ies_id=398

[chalamala]

brachynema... Frightening fish ! Too big for my tanks !
The dark one is back to the shop, I hope the 3 other ones don't belong to the same species...

[Viktor Jarikov]

I'd say that yes we observe differences in the aluminum cats in the hobby (in the US at least) but AFAIK we are not sure how to pin them down to IDs. Nigrodigitatus appears to be the most common one, no? http://www.planetcatfish.com/common/spe ... ies_id=519

Agreed, a good revision is needed.