Once a pair has been formed you should remove the other fish from the aquarium, since breeding Oscars are highly territorial and can hurt intruding fish. If the spawning does not commence immediately there is not easy fix that can kick start it. What you can do is provide the pair with suitable conditions and wait for the spawning to start. The courtship behaviour can be very violent – sometimes too violent and resulting in the death of one of the Oscars before any offspring has been produced. Oscars will do well in softacidic wateras well as in harder alkaline water, as long as you avoid any extremes. Keeping the conditions similar to their native home in Central America is always a good idea. Frequent water changes are important to ensure suitable water chemistry and low levels of soluble waste. Do not change more than 25 percent of the water at once. Changing 20-25 percent of the water once or twice a week is a good rule of thumb. Efficient filtration is also required since Oscars are renowned for being messy eaters and producing plenty of waste. If you have a 50 gallon aquarium you should ideally use filtration that is recommended for a 100 gallon aquarium.
Feed the pair bait fish or frozen fish. Prawns, crickets, earth worms and other meaty foods are also suitable. Some Oscar keepers feed their fish raw meat from cows and pigs, but this is highly unadvisable since such meat include too much animal fat and can harm the health of your Oscars. Remember that wild Oscars feed mainly on small fish and eating cows, pigs, sheep etc are therefore very unnatural for them. Pellets should also be avoided since a majority of the pellet will slip through the gills of the Oscar and never end up inside the stomach. Your fish will still be hungry and the water will be polluted with uneaten pellet material.
An Oscar pair will typically dig a pit in the substrate or choose a hard surface, such as a flat stone, as their spawning site. Both the male and the female Oscar will guard and care for eggs and fry. The will be extremely protective and aggressive during this period and should be kept alone. Just like with many other cichlid species, it is common for an Oscar pair to fail their first attempts to raise offspring. Newly hatchedbrineshrimp is a suitable first food for Oscar fry. You can feed the powdered flake food, but they will grow much faster on brine shrimp. When kept on a brine shrimp diet the fry will be 1.5-2.0 inches long after three months. Keep in mind that one Oscar pair is capable of producing tremendous amounts of offspring. You might have to cull the batch if you can’t provide all the young Oscars with suitable housing.
