For fishes kept in aquariums, the Oscar fish is probably one of the most intelligent and "human-like" found. Personally, I have found great joy in keeping fishes from the Cichlidae family of which the Oscar belongs to. They seem to exhibit certain traits which make aquarium fish keeping all the more enjoyable. These are some of the behaviours exhibited by the Oscar fish.
You bet, especially when you consider its purposiveness in its movements and intentions. Comparing it to other fishes like the kois, goldfishes, barbs and danios, the Oscars move about with more awareness. At times, it looks as if the Oscars knew what they wanted and how they would move about to achieve their goal. It does not swim aimlessly or dash about like the barbs or danios. Rather, they have that "exploratory" look about them. Not unlike a predator!
Would you not consider placing your hand inside the aquarium to allow the Oscar fish to brush themselves against the palm of your hand just like how a cat or dog would do so to you? Seriously, the Oscar fish can be affectionate if you know how to deal with it. A word of caution though! I wouldn't dip my hands in fingers first because little Oscar might think that a bunch of worms (food!) have just entered for dinner! Rather, I would make a fist and dip it into the aquarium before slowly opening my hand. That's the rule of thumb (pun intended) for dipping hand into an aquarium especially when you are dealing with a fish which eats meat.
An Architect and Builder
Don't bother decorating a tank which you intend to house an Oscar cichlid. Just like most cichlids, the Oscars like to rearrange the gravel or rockwork in the tank. It is impossible to satisfy them with your own styling as far as how an aquarium decor would look like. These little fellas would scoop the gravel in their mouth and throw them wherever they fancy. Then, they will guard their territory, especially when they have made a nest for themselves. So, save that effort of yours.
The way the Oscar fish struts itself majestically - with striking colours on its body, whilst protecting its territory in the tank is a sight to behold. Fishes smaller than the Oscar might get eaten up or get bullied to a corner. Bigger fishes would fare better but the Oscars would not hesitate to pick a fight when it feels that its territory is being threatened.