Oscar

Scientific Name: Astronotus Ocellatus

Distribution: The rivers of Peru, Brazil and French Guyana

Size: Up to 16" /40cm

Common Names: Oscar Cichlid, Velvet Cichlid, Marble Cichlid

Temperature: 72F/23C to 85F/29C

pH: 6 to 7.5

Oscars would have to be about the most popular South American cichlids in the aquarium hobby, and with good reason. They are attractive, large cichlids that interact with their owners from a very young age. With multitudes of colour morphs available, there is an Oscar to suit just about anyone. Often acting more like a dog with fins, Oscars soon steal the heart of anyone that falls for that cute little "Take me home and love me!" dance that most juveniles will display in the tank at the local pet shop. Unfortunately, this outgoing personality can lead to problems for many people who buy Oscars, unprepared for the size these fish can obtain. Many pet shops have tanks full of full-grown Oscars than have been returned once owners realise that they are unable to provide them with the tank size these fish require.

Oscars are highly intelligent fish, each with its own distinct personality. At times, they can be likened to a young child, with all the mood swings and temper tantrums that go along with that. They have a long lifespan, 15 to 20 years, so if you are planning on buying an Oscar, you should be prepared to a life time commitment.

In the wild, Oscars claim large territories and years of tank breeding has not dulled that instinct. Don't be surprised if your Oscar decides that the area around him or her tank for several feet also belongs to them, and reacts quite strongly when an unknown or potentially dangerous creature, such as the cat, enters that space.

A single Oscar requires a minimum of 55 to 75 gallons/210 to 285 Litres to grow up healthy. The worst thing that can happen to these fish is to be kept in a tank that is too small. If you want to keep a pair, then you'll need a tank over 75 gallons/285 litres. The tank should be wide rather than tall, with a minimum width of 18" /46cm, otherwise your Oscar will not have enough room to turn around. Substrate should be fine gravel, similar to what you would find in their natural habitat. Oscars are diggers, so make sure that the gravel is rounded, otherwise you run the risk of them injuring their mouths during one of their mammoth excavation sessions. Live plants do not tend to last very long in an Oscar tank, as they soon come to be considered toys. Even plastic plants will be dug up and thrown around the tank, so if they are used, you should make sure they are well secured. Caves of some kind are also necessary, and one cave should be provided for each Oscar in the tank. This will allow each fish to have its own "space" to retreat to and feel secure in. Large clay pots are good for this, as is PVC pipe and rock formations have been well siliconed together. Anything that is added to an Oscar tank should be tested for sturdiness. Oscars are destructive fish, especially after they reach maturity at around 9 to 10" /23 to 26cm and about 2 years of age. It has been said by a lot of people that Oscars are not appreciative of bright lights, so this should be taken into account when setting up tank lighting.

In the wild, Oscars live mainly on insects and small crustaceans. They will occasionally eat smaller fish, but this is very much an opportunistic thing, rather than a regular part of their diet. They need a diet that is high in protein and also has a certain percentage of vegetable matter. Home made foods, such as the beefheart recipe, are ideal for an Oscar, supplemented by treats of insects such as crickets, mealworms and earthworms, and frozen foods like brine shrimp and daphnia. High quality pellets are also acceptable, but should be supplemented with some variety of high protein food.

Oscars do tend to get a little picky about their food from time to time, suddenly deciding that their staple food is no longer what they'd like to eat. They can go a fair time without eating, two to three weeks before it starts to take a toll, so if you have an Oscar that is refusing to eat, don't worry. Just remember, we have a much better idea of what is healthy for our fish, and sometimes a little "tough love" is necessary.

Oscars, like most large cichlids, are territorial, so finding compatible tank mates can be a challenge. Many people have had success with other species of medium or large cichlids, such as Jack Dempseys, Severums, Firemouths and Convicts. Keep in mind that anything you add to your Oscar tank should be added while both fish are still juveniles. It is often the case that Oscars will grow "attached" to fish they grow up with and will live happily with fish that would otherwise be considered a threat or a food source. The biggest problem with finding tank mates for Oscars is that each fish is so individual that what works with one fish, may be a disaster with another. One of the most commonly found tank set ups for Oscars is a single fish or a pair of fish in a 75 gallon/285 litre tank with a large armoured catfish, such as a plecostomus.

For all their bluster and performance, Oscars are not considered a highly aggressive species of cichlid and therefore are incompatible with more aggressive fish such a Red Devils, Midas, Jaguars and Dovii. That being said, it is possible that one of these cichlids might work as a tank mate, it all depends on the Oscar.

Many people are concerned about keeping a lone fish in a tank, thinking that the fish would get lonely. This is not the case. In the wild, an Oscar would claim a territory of several square meters and would consider anything intruding into that space as a threat. Therefore, a lone Oscar in a 75 gallon/285 litre tank would be quite happy to be all on its lonesome, happily defending his or her territory from anything that comes near enough from visitors to other pets.

Oscars reach sexual maturity at around two years of age. There is no visible difference between males and females, and the most common form of sexing is to wake up one morning and find that you have fertilised eggs in your tank. It is possible to sex Oscars by venting even at a young age, but this should NOT be attempted unless you are completely confident in what you are doing. Venting is extremely stressful for the fish and can result in damage to the fish if not done by someone who is experienced. Large Oscars can be vented by sight, if you can persuade your fish to line itself up at the front of your tank long enough to take a peek. A good way to confirm that you have a mated pair is to purchase 6 to 8 juveniles and let them grow up together. This way, you are almost guaranteed to get at least one male and one female, and growing up together will cement a pair bond.

Courting begins with typical cichlid flirting, involving tail slapping and lip locking. This can continue for several weeks before eggs are laid, especially with the first spawning. Oscars generally lay their eggs on a flat slab of rock, and will often dismantle and reassemble their tank to provide themselves with a spawning space suitable to their needs. The eggs are white when laid and will turn a pale amber colour once fertilised. Mature Oscar females will lay eggs without having a male in the tank and sometimes females kept together will go through the full motions of spawning with one female taking the role of the male. Hatching usually takes place within 3 days, although they will hatch sooner in a tank with a higher temperature. The fry are then cared for in typical cichlid fashion. Any tank mate should be removed at the first sign of spawning, as even fish that have been tolerated up till then will be considered a threat. Bottom feeders of any kind will be particularly harassed, as they would consider any eggs laid as a tasty treat.

It is common for many Oscar pairs to eat their first few spawning, although most generally figure out what their supposed to at some point along the way. Many people remove the eggs after they have been laid to prevent this, but this also has the effect of not allowing the parents to figure out how to do things for themselves, resulting in all subsequent spawns being eaten. It depends on whether you have the ability to cope with up to 1000 fry as to what you decide to do if confronted by a spawning pair.