Meet Oscar, A Fish That's Usually "King of the Tank"

Posted by Erin McDade
Oscar Fish

What do you give the actor that has everything? An Oscar!

The oscar fish (scientific name Astronotus ocellatus) is a genus of cichlid freshwater fish commonly kept in freshwater aquariums. The tiger oscar, which is very similar to the wild oscar, is the most popular variety, but several other types include the velvet cichlid and marble cichlid. Albino oscars, leucistic (primarily white), and xanthistic (yellowish) varieties are also available. They are indigenous to Peru, Ecuador, the Amazon, Brazil, and French Guiana, and they can be found in the Amazon River basin.

About The Oscar Fish

Oscars are predatory aquarium fish that eat various smaller live fish species such as bloodworms, crustaceans, and aquatic insect larvae. These feeder fish generate suction by rapidly expanding their mouths to suck in smaller species. Although the Oscar is native to South America, its popularity as an aquarium species has resulted in numerous introduction events worldwide. In tanks, they may be fed commercial fish food, live food, or frozen food. Like most fish, they enjoy live plants and a comfortable water temperature appropriate to their species. They have a lifespan of 10-20 years, and need a 55-gallon tank for a single oscar or a 75-gallon tank for two, making tank size an important factor in choosing this fish.

Suction Feeding

Predatory fish take advantage of water viscosity. A giant wall of water is drawn in when the Oscar opens its mouth rapidly. Water molecules, unlike air molecules, attract each other by the mechanism of cohesion. Smaller fish that get caught in the wave are sucked into the Oscar's mouth. Aside from aquarium fish, many other marine species benefit from suction feeding. Some notable suction feeders include sharks, newts, catfish, and many others.

Breeding & Brooding

Oscar fish will naturally protect their territories by driving away any other fish that approaches too closely and eating anything small enough to fit in their big mouths, but Oscars are highly cautious when it comes to their children. When eating, the oscar fish will protect its young and avoid sucking them up. This is referred to as "brood care," and it is a form of parental care seen in many fish species. Unlike other fish, the female oscar will protect its offspring until they are large enough to leave and develop their own territories.

Aquarium Behavior

Oscar cichlids will sometimes stake a claim to a particular area of the aquarium. They will be hostile towards any tank mates that intrude on their newly formed territories within the aquarium or lake. The territory size varies depending on the size and aggressiveness of the fish concerning its surroundings. If an oscar fish has developed a territory, it will fiercely protect that territory by chasing other fish away. Often aquarists will be forced to remove the oscar from their tropical fish tank as it will bully other fish, especially small fish, even in a large tank. Fellow cichlidae make good tank mates for oscar fish, as they will usually hold their own against this territorial behavior. Common names of good tank mates include Convict Cichlids, Jack Dempseys, South American Cichlids, and Firemouth Cichlids, to name a few. Smaller fish like goldfish and tetras will quickly be sucked up, so be careful what you add to your tank!

Several ornamental varieties have been developed for the home aquarium industry. These include albino, leucistic, and xanthistic forms and forms with greater strength and quantity of red marbling throughout the body. Red tiger oscars are strains with marbled patches of red pigmentation, whereas red oscars are strains with a primarily red coloration of the flanks. Individuals have different patterns of red pigmentation. Long-finned varieties have also been grown in recent years. All of these varieties make a great addition to an oscar tank. Which will you choose?

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Meet Oscar, A Fish That's Usually "King of the Tank"