Owner recognition seems to be one aspect that I would say merits using the term "intelligent " of a fish. I had an oscar that would not eat food given to it by someone watching our house while on vacation until she left the room and peeked around the corner and saw it chowing down. It never did that with me it always did the happy dance, its time to eat when it saw me. I now have a Midas that could care less who feeds it, it takes food from anyone. Does that make the Midas less intelligent than the oscar? Or more?