Did you know fantastic help is an anagram of Planet Catfish? This forum is for those of you with pictures of your catfish who are looking for help identifying them. There are many here to help and a firm ID is the first step towards keeping your catfish in the best conditions.
Rhinelepis do not have adipose fins and the fish in the picture does. And they dont really have the ridges along the dorsal flank, they are far more flattened.
I don't think it's a Pseduacanthicus, there is no distribution of them south of the Amazon drainage, AFAIK. (We do not have any listed for the "La Plata" region, for sure).
Ive had a quick flip through the Hypostomus genus. I dont think Hypostomus should be discounted there are 2 variations in the teeth that I can see, the more V shaped spatula (Panaque like) and the wider angled rake like ones, like this Hypostomus has. This
Off the top of my head, among hypostomines the only groups lacking the eye lobe are the rhinelepins and Corymbophanes as well as the deepwater P. bathyphilus and H. pankimpuju. However, the omega eye may be retracted, and the reflection/lighting is obscuring where it would be in the close-up.
- Milton Tan
Research Scientist @ Illinois Natural History Survey
has the same shape teeth and is also from the La Plata region in Uruguay.
My friend's first impression and mine were to think in Hypostomus genus. Two months ago, my friend captured a few Hypostomus commersoni, and the teeth are very similar.