Emerald cories have had their scientific name changed a gazillion times. Mostly it has to do with the fact that they have more than 10 rays in their dorsal fin, where members of the corydoras sp. have only 7. Scientifically, emerald cories are brochis splendens. They are also true bottom dwellers, usually only racing to the top of the water to gulp air occasionally.
They can get to about 3 inches, and are some of the larger armored bottom dwelling cats. Unless you keep them in numbers of about 5 or more, they are usually very shy.
That's what you have in your photo.
Sometimes I get the feeling that the whole world is against me, but deep down I know that's not true. Some of the smaller countries are neutral. Robert Orben