Breeding: Oscars will pick one mate and have batch after batch of fry once they get started. They are egg layers and have anywhere from 200 - 2000 eggs at once and do this about every month. They will usually lay their eggs on a large flat rock such as slate. Oscars are very diligent parents, protecting their eggs/fry aggressively. Do not have any other fish in the tank with a breeding pair as they will most likely seriously hurt or kill other fish to protect their young.
How to breed oscars:
Getting Ready: You will need at least three tanks. 1) A 180 U.S. gallon tank to establish your mating pair if you don?t have them already. 2) A 100 U.S. gallon tank for the parents-to-be. 3) At least a 55 U.S. gallon tank for the fry to grow out in. Breeding Oscars is not for everyone and especially not for people new to the fish keeping hobby. In my opinion they are hard to breed, but when they do spawn they can have anywhere from 200 - 2000 fry at a time and they repeat this process every month or so! You need to have some way to get rid of all these Oscar fry and even as popular as they are this can prove to be a daunting task. Before you take up breeding Oscars, keep in mind that it can be quite hard to sell or find homes for 200 - 2000 fry every month.
Getting the Mating Pair: Chances are that you will not get a mating pair by going in to the pet store and picking out two Oscars. The best way to go about getting a mating pair (although this method is still not guaranteed) is to buy about six (6) juvenile Oscars and keep them in a tank together and let them pair up naturally. As you know Oscars are large, messy fish that can be aggressive so a large tank is necessary for this. (a minimum 180 U.S. gallon as mentioned above) When the Oscars have paired up you can remove the pair to the 100 U.S. gallon parents-to-be tank (also mentioned above). The rest of the Oscars in the tank can be returned, sold or kept if you are up to the task. If you do decide to keep them, remember Oscars require lot of care and attention.
Getting the Pair Ready to Breed: Now that you hopefully have your mating pair you will need to get their home ready for breeding. You need at least a 100 U.S. gallon tank with good filtration and pea sized or smaller gravel or sand as a substrate. You will also need a large flat rock such as slate and a cave or pot. You can decorate with driftwood and such but I don?t see this as necessary. Keep up with your water parameters (as you always should) and change the water regularly. All you have to do now is watch for the mating ritual signs listed below.
Mating Rituals: Mating rituals include moving the substrate around in the tank, cleaning the slate and rubbing against the rocks or slate, shimmying their bodies and fins against each other, and lip-locking.
Breeding: When you start to see the above mentioned signs of mating it is suggested that you do a rather large water change of about 75% and raise the temperature to the middle 80?s not to exceeding 85? F and subdue the lighting. This helps encourage the mating process. When they are ready to lay and fertilize the eggs they will start spending a lot of time around the area they plan on having the eggs. (usually the flat rock/slate) Two females have been known to go through all the motions and even lay eggs, so you could still not have a male/female pair. It also needs to be mentioned that it may take several times for them to get it right. Don?t get discouraged if they don?t have fry the first, second, or even third time. When you do have eggs make sure they are fertile. The way you do this is by the color of the eggs. After about 24 hours, if the eggs are white they are not fertile. They will be a yellowish or tan color if they are fertile. All unfertilized eggs need to be removed. Just be careful of attacking parents. Oscars are very diligent parents. They will guard the eggs/fry very aggressively. I also need to mention that there should be no other fish in the tank with a breeding pair. The parents will attack and can seriously hurt or kill anything they see as a threat to their eggs/fry.
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