Red Oscar Fish: Most people choose Oscars over any other fish because they do possess a personality. I know that's hard to believe but it really is true. Oscars seem to be able to portray what mood they are in. At feeding time they are excitable and swim around the tank like it's the last meal they are ever going to get. On the other hand, they can often sulk like little children if something has happened which they don't like, such as a water change, or rearranging the aquarium.