Breeding Oscar Fish

There's nothing more exciting than watching a pair of Oscars going through the breeding ritual and then getting down to the business of laying eggs. However, if the eggs hatch then there is every possibility that you could have several hundred babies to deal with. Obviously, you are not going to be able to stop a pair of Oscars breeding if they want to. However, purposely going into breeding Oscars is something that should be thought through very carefully. Before you even start trying to breed Oscars, you should already have plans on what is going to happen to all the babies that you will end up with.

Male or female

Before you can breed Oscars you need a male and a female. Unlike many other tropical fish where there is a distinctive difference between the male and the female, there is actually no way to tell the difference between the male and female Oscar just by looking at them. Some people claim they can sex an Oscar by comparing fin shape, colouration or even temperament. However, these claims should be dismissed. Oscars are what we call "monomorphic", translated to "one shape". This means that the male and female look exactly the same.

There are really only two known ways of successfully telling apart a male from female Oscar fish. The first involves a process called "venting". Somebody who knows what to look for will be able to examine the genitals of the Oscar fish. By comparing the shape and size of the opening will determine the sex. The second and absolute 100% guaranteed way of sexing an Oscar is when you see the female laying eggs and then the male fertilising them.

If you are lucky enough to witness Oscars laying eggs then you may want to take a little peek at the underneath of both fish. You will then see the difference between the female and male genitals. The female's genital papilla is what most of us refer to as an egg tube. It's fairly wide at the end and whitish in colour and sticks out quite far. When she's not laying eggs it retracts completely inside her. The male's genital papilla is very different from the females as he only has a small spike from which sperm is deposited from.

egg tube

Female's egg tube

Obtaining a male and female

This is actually a task that is easier said than done. In the Cichlid fish world, the female will normally choose a partner to pair up with and breed. Therefore it's not just a case of buying two Oscars and waiting for them to breed. You might get lucky and end up with a breeding pair, however, the chances are you've either bought two females, two males or a pair of Oscars that just aren't interested in breeding with each other. In order to increase the chances of finding a breeding pair, you will need to get several Oscars and keep them together in the same tank for a few months. What you hope will happen is two of the Oscars will eventually break off and form a pair together.

If you've already got an adult Oscar then you could play cupid and try and find a mate. This would involve bringing home adult Oscars for basically what would be a date with your own Oscar. In order for you to find your pair this way I think you would have to have a fairly good relationship with your local fish store because obviously, you may have to return the Oscar several times until you find what you're looking for.

Signs of possible breeding

Before Oscars ever start laying eggs you will start seeing some very strange behaviour. The female Oscar will want to test the male Oscars strength and she does this by playing a kind of tug-of-war with him. This procedure is called "jaw locking" and as the name suggests, the Oscars grab onto each other's mouths and literally try and drag each other around the tank. As well as the jaw locking, you may also see the Oscars chasing each other sporadically, often trying to nip each other at the rear end. The jaw locking and chasing will then lead onto the Oscars looking for an area in the tank where the eggs will be laid. If you've got a flat rock in the tank then the chances are they will choose this area. They will then start scrubbing the rock with their bottom lip in order to make it nice and clean so the eggs stick properly.

If the female is going to lay eggs then there is a very good chance that the egg tube will protrude at some stage during the cleaning process. You may even see the males sexual organ sticking down at the same time. However, I've seen this before and eggs were never laid so it's never an absolute guarantee that something will happen.

Oscars finally lay eggs

When the female Oscar is ready to start depositing her eggs on the rock you will probably notice the egg tube protruding from her. The egg laying will probably start suddenly, she will start swimming back and forth over the rock whilst wiggling slightly. If you look carefully you will see small white eggs on the rock. As she swims back and forth the male will follow her and fertilise the eggs. It's impossible to say exactly how long the egg laying process will take, it depends on how many eggs they lay. Sometimes they can completely cover a large rock with eggs, other times they don't lay that many.

Once the eggs have been laid on the flat rock both male and female Oscar will then oxygenate the eggs by using their two pectoral fins as fans. As well as oxygenating the eggs, they will also remove any eggs they deem bad. Therefore don't worry if you see them eating one or two eggs every now and then.

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Fertilised Oscar fish eggs

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Oscar fish fry 2 hours old

Eggs that have been successfully fertilised will change from white in colour to a tan brown after a few hours. The eggs will then take about three days to hatch. At first, you will see the eggs shaking slightly as the fry start to break out of the shell. Once the fry completely hatches they will have a yolk sac hanging below them, this will feed them for approximately four days. Once the yolk sac has been used up they will then need to be fed.

You have Oscar fry

If your intentions are to keep the baby Oscars then you will need to take them away from the parents and put them in their own tank. You're not removing the fry for protection, you will need to put them in the tank that has pristine water conditions. Also, in order to feed and help them grow properly, they will need to be completely on their own without any interference from other fish in the aquarium.

Feeding your fry

Feeding Oscar fry is not as straightforward as feeling any other fish. The Oscar fry has got tiny mouths and it's doubtful whether you will have any suitable foods to hand. However, there is a wide variety of baby fry food to choose from nowadays so your fish store should have something suitable for you to use. Alternatively, have a look on eBay, you can get just about anything you want off there.

Brine Shrimp

Brine shrimp are by far the best food to feed to your Oscar fish fry. People have been using baby brine shrimp as fry food for many years. Brine shrimp are packed with all the nutrients and proteins that your Oscar fry needs to grow into healthy adult fish. Brine shrimp also trigger the hunting instinct so your baby fry is more likely to react to baby brine shrimp than long living food.

Baby brine shrimp are very easy to culture. You can buy eggs online and keep them for many years in a cool dry place. Brine shrimp eggs can be hatched using a brine shrimp hatchery and will normally be ready to be fed to your fry within 24 - 48 hours. It's quite easy to make your own brine shrimp hatchery, alternatively, you can purchase them online for very little money.

This article will give you good information on what other foods you can use to feed to your baby fry.

Brine shrimp hatchery

If you fancy making your own brine shrimp hatchery then visit this article, it gives you some really good information on how to make one for very little money.If DIY isn't your thing then purchase a off of eBay

Artificially hatching Oscar eggs

If you decided that you want to breed Oscars with the intention of selling the fry then you will need a spare aquarium in order to raise the fry. Your spare aquarium must be quite big but more importantly, it must be fully cycled ready to take the fry. Baby fry will not be able to withstand poor water conditions so there's absolutely no point in trying to raise them in an aquarium that hasn't already got an established biological filter running on it.

After the eggs have been laid and they have changed colour to a tan brown, you can then remove the stone and eggs and put them in your spare tank. In order to replicate the procedure where the fish oxygenate the eggs, you will use an air stone. Prop the stone up at a slight angle using the air stone. When you switch the air stone on you should see the bubbles rising up the side of the stone and then flowing across the eggs. These oxygenated bubbles will take the place of the fish fanning them with their pectoral fins. 

The fry will hatch after about three days. They will have a yolk sac which will sustain them for about three days. They will now be ready to be fed on the live baby brine shrimp. Once the fry reaches .5 cm and starts to resemble Oscars you could try feeding them on baby fry flake. However, keep on feeding them on the brine shrimp until they are big enough to eat normal food.

Simulate natural breeding conditions

Oscar fish breed in the rainy season in their natural environment. The conditions in your home aquarium will probably remain the same all year round. Your Oscar will not know when it's time to breed. It's not uncommon for a female Oscar to produce eggs not long after a large water change. Basically, the Oscar has been fooled into thinking that it's raining and therefore it's the time of year that she should be reproducing. So using this knowledge there is a way that you can try and trick your Oscars in thinking that it's the rainy season and time for making babies.

Simulating heavy rainfall in your aquarium is not that difficult. Extremely heavy rain will cool the temperature of the water slightly so drop the temperature of the water by about 2°C. There are various ways you can simulate rainfall in on the water. The easiest way is to use a spray bar which when positioned slightly above the water will simulate the sound of rain falling on the water. Even though a lot of canister filters do come with spray bars, it might be best to actually modify your own spray by using a water pump. This way you can switch it on several times a day to simulate rainstorms. Alternatively, use a watering can and spend five or 10 minutes sprinkling the surface of the water a few times a day. 

During your rainy season simulation period feed your Oscars on insects, shrimps and bloodworm. A cheap way to obtain the perfect insect is to hatch mealworms. 

Target fish

Don't worry too much if you do have another Oscar or two in the aquarium. A breeding pair of Oscars will often not allow any other fish near the eggs. Target fish are often used to divert aggression from within the breeding pair to any other fish in the aquarium. However, this is only ever done in very large aquariums.

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