Oscars (also known as velvet cichlids or Astronotus ocellatus) breed extremely well in captivity. In fact, they breed so well that often 90% of eggs lain turn into thriving and growing baby Oscars. Considering that a female Oscar can lay anywhere up to 3000 eggs, this means you will have a lot of baby Oscars on your hands. Unless you have a home or market for those babies, then you really should not attempt breeding them.
Equipment Needed
You will need at least three tanks. One can be ten to fifteen gallons, but the others need to be over fifty gallons. Many experienced Oscar breeders use 100 gallon tanks as the breeding tank. Remember that Oscars are aggressive fish that often can barely tolerate their own company, let alone that of another Oscar.
You will need pumps, heaters, filters, thermometers, yards of air hose and a virtual quarry of air stones. Many Oscars will rip out all aquarium decorations except gravel but some don’t mind flowerpots on their sides or stones safe for the aquarium. You also need a flat stone for the female to lay her eggs on. You have to cover the intake valve of the filter with foam to be sure the fry aren’t sucked up and killed.
In case you know for a fact that the Oscar pair get along, you need to provide a hiding place for the Oscar that gets harassed the most. You also need lids with weights, as Oscars are strong enough to jump out of a tank.
Male Or Female?
Despite some old fish wives’ tales, there is practically no way to tell a male from a female Oscar. Size doesn’t make a difference, nor color, nor fin shape. The male has a small thorn-shaped organ on his underside if he’ll let you look. The female, however, has an ovipostor or egg tube on her underside that also looks similarly to the male’s organ. The best way to sex an Oscar is to note which one lays the eggs.
Oscars are unusual fish in that they will not spawn with any Oscar of the opposite sex. They actually have to like the fish in order to want to spawn. If not, then expect for the larger of the pair to eat the smaller of the pair. Try to keep the pair the same size. An Oscar does not get sexually mature until they are sixteen months old, although they will start some spawning behavior when they are only a year old.
Spawning
Oscar spawning behavior lasts a long time. This includes chasing, slapping tails, body-slapping, and finally lip-locking. One then drags the other by the lips to the flat stone. The female lays eggs in bursts of a few hundred at a time and the male fertilizes them.
And then the pair become very placid towards themselves as they guard the eggs. Not all Oscars make such great parents. Sometimes you get a Psycho Fish that has to be removed. Your Oscars may look like they are eating the eggs, but they aren’t. Sometimes they place the eggs in their mouth to protect the eggs.
Hatching
Oscar eggs hatch after three days. The fry don’t need to eat for another four days because they emerge from their eggs with a tiny yolk sack attached to them. You need to be sure the fry get food such as baby brine shrimp or commercially available liquid fry food. When the fry get to be an inch and a half long, their parents will mistake them for dinner. Either the parents or the fry need to be removed.
Some people like to move all of the eggs or fry to a ten or fifteen gallon tank and take care of them as surrogate parents. Since the eggs are all on one flat rock, you just need to move the rock. You need an airstone in the tank positioned high, so the water flow doesn’t disturb the eggs too much.
The baby Oscars are ready to go to their new homes when they are about two months old.
References:
Aquatic Community. “Breeding Oscar Fish.” http://www.aquaticcommunity.com/breeding/oscar.php
Oscar Fish Lover. “How to Breed Oscar Fish.” http://www.oscarfishlover.com/breeding-oscar-fish
Fish Channel. “Oscar Fish Breeding.” Dr. Robert J. Goldstein. http://www.fishchannel.com/freshwater-aquariums/fish-breeding/oscar-fish.aspx
Personal experience
