I have seen many young wels catfish, but that head looks pretty strange...something doesn't seem right (especially the eyes)
but the first thing i noticed, is the dorsal fin. Wels catfish have a rounded, thin dorsal fin, not an angular one like your fish.
Also, the whole fish seems too slender for a S. glanis.
So I don't think your catfish is a S. glanis, but it may be another Silurus sp.
Again, I'm not an expert in identifying catfish, so I can surely be wrong, but in my opinion, the fish seems kind of strange to me.
I have a fish breeder (sells fish for food and stocking ponds, lakes,...) pretty close to my place.
He often gets S. glanis, from tiny 5cm babies to monsters with about 100kg or even more ( but 100kg+ ones not so often).
If you want, I'll show him your fish next time I visit him, maybe he knows for sure if it's a S. glanis or not.
oh, the fish seems to be way too skinny, please feed him earthworms, he should fatten up in no time.