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.
I've been looking at a lot of images of Corys with this approximate form C. agassizii, C. ambiacus and C. melanistius (and probably others) all look pretty much the same to me. Is there some good way to distinguish them (other than "gestalt")?
The fish is a Corydoras delphax, distinguishing between these C. melanistius, C. ambiacus and C. agassizii is not always easy. There are certain features in each species which separate them and it would take far more time than I have right now to explain them all. The best place to start is by checking out known images of the species. Many can be found here in the Cat-elog and also on my own site Corydoras world.