Well, that's in part what I meant by one photo where the fish is turning a bit too.Second thoughts Viktor the fish I have pictured seems to have a different shaped adipose...
If that's the actual fish and not a generic pic.
That might be a good observation. If you aim to get technical, run through all species of Exallodontus, Iheringichthys, Propimelodus, Pimelodus, Pinirampus, and Pimelodella for starters and see if you find only 10-20 matches and we'll go from there
Seriously though, it seems fish like these are very hard to ID to us hobbyists. Still, it'd be impressive to even try. I just have no time, nor motivation. Sorry.