
The Oscar family is popularly referred to as the peacock cichlid or velvet cichlid, especially to American and UK aquarists. I suppose this is due to the beautiful markings on the Oscar Cichlids - the ocellatus or "eye" which is prominently seen on the side of the Oscar's body just like how it appears on a peacock's feather. It is almost like a false eye by the side of the body to deter other fishes from coming near, though I must say that Oscars are usually aggresive in nature and fear no other fishes (unless they are far too big).
I understand that the original scientific name for the Oscar is Lobotes ocellatus as given by Baron Cuvier in the 1800s, though I have no idea how it became the Astronotus ocellatus. Personally, with no disrespect to Baron Cuvier, I prefer the current scientific name for the Oscar.