Astronotus Ocellatus

Datasheet

General Description

The Oscar, scientifically known as Astronotus Ocellatus, is a member of the Cichlidae family within the order Perciformes. Also referred to as the 'velvet cichlid', 'red oscar', 'tiger oscar', or 'marble cichlid', this species is popular among aquarium enthusiasts for its ornamental strains available. Typically reaching sizes of up to 35.0cm and with a lifespan of 10-20 years, the Oscar requires consideration due to its adult size.

Aquarium Setup

The Oscar, also called Astronotus Ocellatus, thrives in tank setups that include a natural-style environment with a soft, sandy substrate, dim lighting, and large driftwood roots and branches. Unsuitable for carefully aquascaped tanks, Oscars have a tendency to dig in the substrate. Regular maintenance is essential, with weekly water changes of 30-50% of the tank volume being necessary. The water conditions should be maintained within a temperature range of 20-28°C, pH between 6.0-7.5, and hardness of 90-357ppm.

Behaviour

Although not overly aggressive for its size, the predatory nature of the Oscar suggests that it should not be housed with significantly smaller fish. Its adult size and predatory habits make it suitable for large aquariums. Compatible tankmates include characids, anostomids, other cichlids, and larger loricariid or doradid catfishes.

Feeding and Diet

As a generalized omnivore, the Oscar feeds on a variety of items such as smaller fish, insects, crustaceans, zooplankton, and vegetation in the wild. In captivity, a high protein diet is preferred, with options including cichlid pellets, live or frozen foods like earthworms, prawns, whitebait, and river shrimp. Care should be taken not to overfeed as Oscars tend to beg for food. Avoid feeding mammalian or avian meat and feeder fish due to health risks and low nutritional value.

Reproduction & Dimorphism

The Oscar is a substrate-spawner, forming extended pair bonds during reproduction. Pair bonding occurs naturally as young Oscars mature, and once a pair forms, other fish should be removed. The breeding tank should have flat rocks or structures for spawning. The species can lay up to 2000 eggs, requiring ample space and resources for raising the fry. Mature males may be larger and more colorful than females, with little external sexual dimorphism.

Habitat and Distribution

Oscars are most commonly found in the shallow, slow-moving or still waters of forested areas. They prefer silt-laden white water habitats, often associating with submerged tree roots or marginal vegetation. Widely distributed in the Amazon region, Oscars have been recorded in countries such as Colombia, Venezuela, Brazil, and Argentina. Commercial breeding plays a significant role in the availability of Oscars in the aquarium trade.