Bas,
You are of course right on both accounts: There is one other cory,
, that is similar. It has a pointy snout rather than the round snout. The pictures show a rounded snout, so that's sorted then.
Looking at Ian Fuller's and H.G. Evers Identifying Corydoradinae Catfish, I'd say C. rabauti, but the book says they are difficult to tell apart, so I wouldn't bet a months salary on it.
Edit: As is typical for when you type too slow to keep up with your thinking (which possibly indicates that I need to type faster, or think slower!), I didn't explain my ID conclusion. The above book says that C. zygatus is a more slender version of C. rabauti. As your fish doesn't look partiuclarly slender, I will go with C. rabauti.
--
Mats