TankMatesTankMates
Sign in
Encyclopedia / Cichlids / Oscar
★New · no ratings yet

Variations

9 kinds · tap one for a closer look

Oscar

Astronotus ocellatus · Tiger oscar, Velvet cichlid, Marble cichlid, Albino oscar

Eats any fish that fits in its mouth and digs up plants.

Local price coming soon
· real AED shop prices, never conversions
45.7 cmAdult size ✓
22–27 °CTemperature ✓
6–7.5pH ✓
540 LSmallest tank ✓
Add to my tankCompare
Tank mates
Check your own mix →
Not recommended
  • Oscar eats animals up to about 12 cm. Neon tetra only grows to 2.5 cm.
Not recommended
  • Oscar eats animals up to about 12 cm. Cardinal tetra only grows to 3 cm.
Not recommended
  • Oscar eats animals up to about 12 cm. Black neon tetra only grows to 3.2 cm.
With conditions
  • Rift lake cichlids like peacock cichlid need hard, alkaline water and a busy, cichlid-only tank.
  • Only a narrow pH range suits both: exactly 7.5.
With conditions
  • Rift lake cichlids like frontosa need hard, alkaline water and a busy, cichlid-only tank.
  • Their pH needs don't quite meet (6–7.5 vs 8–9). Aim between the two and keep it steady.
Compatible
Compatible
Compatible
Compatible
Compatible

110 species in our list are a good match.

Facts checked against sources on 16 Oct 2026. ✓ means a source backs it; ? means no reliable source yet. See sources

Care and water

Hardness ✓5–20 dGH
Group size ✓Can live alone
Temperament ✓Aggressive
Swims at ?Middle
Care level ✓Moderate
Diet Carnivore
Lifespan ✓10–20 years
Size in shops 3–8 cm
Growth Fast

Behavior

Eats any fish that fits in its mouth and digs up plants. Keep alone or with other large, robust fish.

Food

Large cichlid pellets, insects, prawns. Avoid live feeder fish: they carry disease.

Tap a food to see what it is.

Male or female

Oscars show no reliable external differences between the sexes; the breeding tube can only be seen at spawning time.

Health

Common problems. Tap one to see the signs. This is a guide, not a diagnosis.

Breeding

Egg-layer (substrate spawner) · Moderate

Both sexes clean a flat spawning site and both parents guard the eggs. After hatching they move the fry into a shallow pit in the sand. Get a pair by growing on six or more young fish.

Pairing

Buy 6 young fish and let them pair up. Pairs are often visible by 2 years.

Setup

A 125+ gallon (470 L) tank with a flat rock or slate, 26-28 C. Large pairs need a big tank.

What starts it

Big water changes, warm water and rich food.

Eggs

Up to about 2000 eggs per spawning; they hatch in 3-4 days, then fry stay in a pit guarded by the parents for 6-7 days.

Raising the fry

Feed baby brine shrimp, then crushed pellets. Remove fry or leave with the parents. Sort fry often as they grow fast.

Common mistakes
  • Using a tank that is too small
  • Pairing two males
  • Not removing aggressive pairs
Full breeding guide, day-by-day plan and simulator →

Where it lives in the wild

RegionAmazon and Orinoco basins – Brazil, Peru, Colombia & Venezuela
Rivers and lakesAmazon and Orinoco river systems
HabitatSlow rivers and floodplain lakes
Native rangeAbout 1,500 km across
See it on the world map

Plants that suit it

Anubias

The story of the oscar

Sold as small juveniles, oscars grow into 30-35 cm predators that can live 10-20 years and need a tank of about 540 L for one adult. Most aquarium oscars come from commercial breeders in Eastern Europe and the Far East.

Louis Agassiz described the oscar in 1831 from fish collected in Brazil. It became one of the most popular large cichlids thanks to its bold, interactive behaviour. Red, tiger and albino forms are now bred in captivity.

First described by Louis Agassiz in 1831.

  • It is also caught as a food fish in South America.
  • They grow to around 30 cm or more.
  • The eyespot on its tail may confuse predators.

Sources

17 facts checked with sources