Species · Astronotus ocellatus

Oscar: tank size, water and tank mates

FLAG: grows to ~30-35 cm, eats any fish it can swallow, very heavy waste.

Adult size35 cm (13.8 in)
Minimum tank145 US gal
Temperature23–25 °C (73–77 °F)
pH6–7.5
Temperamentsemi-aggressive
Keep in groups ofAlone or pairs
Swimsmid
Shrimp & snailsLikely to eat them

Predator: may eat fish up to about 10 cm.

Check a tank with Oscar

Good tank mates for Oscar

These species share its temperature range and temperament, with no fin-nipping or predation risk under our rules. Still check your tank size and bioload in the checker.

African butterflyfish · Angelfish · Blue acara · Chinese algae eater · Common pleco · Flying fox · Jack Dempsey · Jewel cichlid · Kissing gourami · Pictus catfish · Rainbow shark · Red-tail shark · Sailfin molly · Sailfin pleco · Severum · Striped raphael catfish · Swordtail · Three-spot gourami · Yoyo loach

Avoid with Oscar

African dwarf frog (predation) · Agassiz's dwarf cichlid (temperature) · Amano shrimp (predation) · Assassin snail (predation) · Betta (male) (predation) · Black neon tetra (predation) · Black phantom tetra (predation) · Black ruby barb (predation) · Black skirt tetra (predation) · Bleeding heart tetra (predation) · Bloodfin tetra (predation) · Boeseman's rainbowfish (temperature) · Bolivian ram (predation) · Bronze corydoras (predation) · Buenos Aires tetra (predation) · Bumblebee goby (predation) · Cardinal tetra (predation) · Celestial pearl danio (predation)

Sources

Checked 2026-11-09 · confidence: high. These are cautious community guidelines, not guarantees. Not veterinary advice. Report an error.