Oscar Fish Care Sheet
AdvancedAstronotus ocellatus · cichlid
Oscars are large, intelligent cichlids that require a spacious tank and strong filtration. They are messy eaters and can be aggressive, so they are best kept alone or with similarly sized, robust tank mates.
Quick care stats
Adult size10-12 inches
Lifespan10-15 years
Min tank size75 gallons
Water temp74-80°F
pH6.0-7.5
Hardness5-20 dGH
TemperamentAggressive and territorial
Group / schoolingSolo or bonded pair
Tank matesLarge, robust cichlids or catfish; avoid small fish.
DietOmnivorous; high-quality pellets supplemented with live/frozen foods like earthworms, shrimp, and krill; feed once or twice daily.
What you need (full setup)
🔧 Tank (75 gallons minimum)Oscars grow large and need ample swimming space.🔧 Canister filter (high-flow)Oscars produce a lot of waste; strong filtration is essential.🔧 Heater (300W or more)Maintains stable tropical water temperature.🔧 ThermometerMonitors water temperature accurately.🔧 Sand or fine gravel substrateOscars like to dig; sand or smooth gravel prevents injury.🔧 Water conditionerRemoves chlorine and chloramine from tap water.🔧 Test kit (ammonia, nitrite, nitrate, pH)Regularly monitoring water parameters is critical for Oscar health.🔧 Durable decor (driftwood, rocks, plastic plants)Oscars rearrange their environment; hardy decor provides enrichment.
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Common health issues
- Hole-in-the-head disease (poor water quality)
- Overeating and bloat
- Aggression towards tank mates
⚠️ For any sign of illness (not eating, lethargy, swelling, retained shed), see a qualified exotics vet. Care sheets are general guidance only.