Oscar
Astronotus ocellatus
Minimum Tank
75 Gallons
Adult Size
14 inches
Temperature
74-81°F (23-27°C)
pH Range
6.0-8.0
Lifespan
15 years
About Oscar
The oscar is a large, intelligent cichlid from the Amazon basin in South America, widely regarded as one of the most personable freshwater fish available. Oscars can grow to 14 inches and are known for their dog-like behavior, including recognizing their owners, begging for food, and even allowing themselves to be petted. Wild oscars are olive-green with orange ringed spots, while captive varieties include tiger, red, albino, and lemon patterns. They are powerful, messy predators that rearrange their tanks by moving substrate, uprooting plants, and repositioning decorations to suit their preferences. Oscars are long-lived fish that can survive over 15 years, requiring a significant commitment from their keepers.
Care Requirements
Tank Setup
- • Minimum 75-gallon tank required
- • Temperature: 74-81°F (23-27°C)
- • pH: 6.0 - 8.0
- • Category: Cichlid
Diet & Feeding
- • Diet type: Carnivore
- • Feed 1-2 times daily
- • Varied diet recommended
Tank Mate Compatibility
Compatible With
Avoid Keeping With
Care Tips
Expert Tips
Oscars need a large tank of at least 75 gallons for a single fish, with 125 gallons or more recommended for pairs. They are extremely messy eaters that produce heavy bioload, requiring powerful filtration rated for double the tank volume and weekly water changes of 30-50%. Feed a varied diet of quality cichlid pellets as a staple supplemented with frozen foods and occasional live treats, but avoid feeding feeder goldfish, which offer poor nutrition and can transmit parasites. Use sand substrate and minimal decorations, as oscars will rearrange everything. They are susceptible to hole-in-the-head disease, which is linked to poor water quality and vitamin deficiency.
Quick Facts
284L
Min Tank (75gal)
36cm
Adult Size (14")
15yr
Lifespan
1+
Can Keep Solo
Build Your Perfect Community Tank
Find compatible tankmates for your Oscar
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Rocio octofasciata
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Hemichromis bimaculatus
Convict Cichlid
Amatitlania nigrofasciata
Angelfish
Pterophyllum scalare
German Blue Ram
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Cockatoo Dwarf Cichlid
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Tank Mates for Oscar
Species from our database with overlapping water parameters, compatible temperaments and a realistic shared tank size.
Convict Cichlid
Amatitlania nigrofasciata
easy · 30+ gal
Flying Fox
Epalzeorhynchos kalopterus
moderate · 40+ gal
Jack Dempsey
Rocio octofasciata
moderate · 55+ gal
Rainbow Shark
Epalzeorhynchos frenatum
moderate · 55+ gal
Similar Care Level
Other moderate-care species that suit a comparable setup.
Frequently Asked Questions
What size tank does a Oscar need?
A Oscar needs a minimum tank size of 75 gallons (284 litres).
What water parameters does a Oscar need?
Oscar thrive in water between 74-81°F (23-27°C) with a pH of 6.0-8.0.
Are Oscar easy to care for?
Oscar are considered moderate to care for. They are aggressive fish with a lifespan of about 15 years.
How big do Oscar get and what do they eat?
Oscar reach about 14 inches and are carnivores. Oscars need a large tank of at least 75 gallons for a single fish, with 125 gallons or more recommended for pairs. They are extremely messy eaters that produce heavy bioload, requiring powerful filtration rated for double the tank volume and weekly water changes of 30-50%. Feed a varied diet of quality cichlid pellets as a staple supplemented with frozen foods and occasional live treats, but avoid feeding feeder goldfish, which offer poor nutrition and can transmit parasites. Use sand substrate and minimal decorations, as oscars will rearrange everything. They are susceptible to hole-in-the-head disease, which is linked to poor water quality and vitamin deficiency.