1) Oscars are large fish with insatiable appetites. They quickly pollute the water they are kept in. This means that filtration must be optimal, water changes must occur frequently and overfeeding must be avoided.
2) Oscars may be very cute and personable when they are small, but they grow quickly. In a community tank they will eat other fish. As adults, they require large accommodations.
3) Thought they are widely tolerant of variable water conditions, they do best in water that is neutral and on the warm side. With oscars I have found cool water that is not sparkling clear leads to hole-in-the-head disease.
4) Their diet will need close monitoring. Live goldfish are the staple of many, but they do not provide a balanced diet (unless the goldfish are feed a good flake food before being offered as prey; this is also known as gut-loading). My recommendation is to avoid live fish, as they may harbor parasites. Instead, feed oscars a good pelleted diet that is supplemented with frozen food and an occasional earth worm for a treat.
5) If you are going to breed these fish, plan ahead. The fry are always hungry and grow quickly. Suddenly being confronted with thousands of fry that need tank space can be a nightmare. Incompatibility can be a problem, so have a tank ready to separate the sexes if they start to fight.
