I brought home these 3 Corys today which I classified as being part of the aeneus-chaos-group.
They are very dark in appearance even on light sand as you can see. The fins have a yellowish touch and all have a golden spot on the shoulder obeve the eye. Stomach is very light.
Even though the pics arent too good the first and last one hit the color best. Its a very brown tone. I was guessing aeneus when i bought them but the girl said no its sth different but forgot the name. ;) (After i told them a Syno angelicus was a decorus and the L90 was an Acanthicus and the L134 was a clown pleco hehe she started to get pissed off a bit )
They have a very low shoulder...cruise missile body.
Im not 100% sure from the photos, but i think your fish is Corydoras schultzei. Corydoras schultzei was described in 1940 using fish from a german aquarium strain. This strain obviously still exists. In the description Holly did not show any pictures, but some years later he published a work featuring a photo. This photo clearly shows the fish we know today here in Germany as Corydoras schultzei. Though "the real" Corydoras aeneus comes from Trinidad and looks somewhat different (i've seen a slide of a preserved fish recently), C. schultzei is imo clearly a valid species. Btw: the "normal" aeneus that is in mass breed in SEA seems to be related to a "aeneus-strain" from Pantanal, and isn't imo C. aeneus as well. Im very curious how fish from Trinidad look, but afaik noone has ever exported them from there.´
Ian seems to have removed the picture on his schultzei site (at least i doesn't show on my computer...). This fish is neither C. schultzei nor C. aeneus. Afaik it comes from Peru and seems, as someone already pointed out, to be related with the C. elegans group.
Some synonyms of C. aeneus have already been revalidated (C. venezuelanus, C. schultzei), and there will be further splitting in the future, though what we considered a long time to be C. aeneus isn't imo a species, but a large species group.
Ihave removedthe picture I had identified as C. schultzii. It was not right. there are a number of species that have been resurrected in recent years and may very well prove to be true and valid species, but it needs scientific collaboration to actually prove they really are true species.
Gratz Achim being mentioned in the datz will surely help boost your traffic.
Compared to the other corys these are very much freeswimmers (housed with 3 Discus) the roam all over the tank feeding off the water surface resting on high plants etc. very nice addition