The saddle-nosed Corydoras serratus from the upper Rio Negro in Brazil belongs to the most wanted species of Corydoras. Due to the fact that the saddle-nosed species of Corydoras are in general no schooling fish it is not possible to collect larger numbers of them in an economically senseful way. This and the fact that there were times in which exorbitant prizes were payed in Japan for this species made them real rare in the trade for a long time.
Nowadays there are some breeders of this beautiful species and one of them supplies us with gorgeous bred specimens of Corydoras serratus. It is very interesting that although the breeder uses only parent fish that fit perfectly to the original description the offspring differs much individually in respect to coloration. Some have only a vertical bar under the origin of the dorsal fin instead of the broad horizontal bar over the back. This phenomenon was also observed in wild-collected specimens, but there was a good deal of uncertainty if not similar, but different species were involved. Thus once more the aquarium hobbyists were able to answer a question of ichthyology.