Whether one keeps the wild types or any of the aquarium mutations currently being mass produced, several important husbandry points need to be kept in mind.
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.
6) If you are going to keep a single oscar for a pet, remember that oscars are destructive and may best be kept in a bare tank. One of my wild oscars not only pushed a submersible heater out of the tank, but it also tore apart the filter. Gravel and stones may be quickly rearranged. I was able to keep the heater in place by using silicone to seal a section of egg crate to a corner of the tank; in this protected corner I inserted the heater.
Based on some of the husbandry issues, some might ask themselves: Why would anyone want to keep oscars? They have personality. Many become accustomed to being petted like dogs. I even know of individuals that have been taught to pull a string attached to a bell. And their entire spawning cycle provides a tremendous insight into cichlid courtship.
If you feel you are capable of providing these large cichlids with suitable accommodations, then give them at try.
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