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Astronotus ocellatus - (Agassiz, 1831)

A personable cichlid for larger aquariums and rugged tankmates. JJPhoto.dk


This “personality fish” is one of the best-known cichlids. It may live for 10-plus years, and will interact more and more with its owner over time. Several color and finnage variations available.

Family: Cichlidae

Other common name(s):

Native range:

Habitat: Oscars are prone to “rearranging” their tanks, so care should be taken when setting up the decor. Provide several rock piles (preferably anchored in place to avoid toppling, and not near the glass) throughout the tank in which they can hide. Any plants should be potted and buried in the substrate, floating or anchored to driftwood (Java fern, Java moss). Deep gravel substrate is preferred.

Maximum length: 36 cm (14 in)

Minimum aquarium size: 209 L (55 gal)

Water: Freshwater 22 °C (72 °F) - 26 °C (79 °F)

General swimming level: Throughout the aquarium.


Long thought to be the “food of choice” for A. ocellatus, live feeder fish are not necessary to keep your Oscar healthy and alert. Does best on a variety of foods specifically designed for omnivorous cichlids. Supplement with freeze-dried krill for adults, bloodworms for juveniles.

Aquarium Compatibility

Oscars are generally peaceful, despite their size. Acquire four or more young individuals in as large a tank as possible.


Juvenile Albino Oscar. JJPhoto.dk

Oscars form cohesive pairs and spawn in the open, often in pits dug in the gravel. Albinos and various other color forms are commonly available.


Heavy filtration and frequent partial water changes are a must, as these are messy eaters. Lax attention to water quality may lead to “Hole-in-the-Head” disease.

Reference: 101 Best Tropical Fishes
Image credit: NH
Text credit: KW