Astronotus ocellatus
Oscar
A rewarding companion for an owner who has researched its needs honestly. As with every animal on this site, this profile is a starting point: confirm details with a vet or specialist before bringing one home.
CichlidaeLifespan 10–15 yearsCare complexity 3/5Not a beginner animal
Representative fish photography; individual appearances vary.
At a glance
- Scientific name
- Astronotus ocellatus
- Family
- Cichlidae
- Origin
- Amazon basin, South America
- Lifespan
- 10–15 years
- Adult size
- 25–35 cm
- Weight
- Up to 1.5 kg
- Temperament
- Intelligent and interactive for a fish, but territorial and predatory.
- Activity level
- Moderate; active swimmer that rearranges décor.
- Social needs
- Often kept singly; tank mates must be large, robust and chosen carefully.
- Intelligence
- High for a fish; recognises owners and learns feeding routines.
- Noise
- Silent.
Housing and environment
- Housing
- Minimum 200 litres for one adult, with heavy filtration and a secure lid.
- Space requirement
- A large, sturdy aquarium on a load-bearing surface.
- Temperature
- 24–28 °C.
- Humidity
- Not applicable.
- Exercise
- Needs swimming space more than enrichment.
- Grooming
- Not applicable; depends on excellent water quality.
Diet and feeding
Carnivorous: quality cichlid pellets plus frozen foods; avoid feeder fish, which spread disease.
Behaviour and compatibility
Digs, moves ornaments and can sulk after tank changes; aggressive to smaller fish.
- With children
- Fine as a display fish; children should not put hands in the tank unsupervised.
- With other animals
- Will eat any fish that fits in its mouth.
- Training difficulty
- Can learn simple feeding cues.
Health
- Hole-in-the-head disease
- Ich
- Bloat from poor diet
- Ammonia poisoning in undersized tanks
Most problems trace back to water quality; test weekly and change 25–30% of the water weekly.
Special care requirements
See the housing, diet and health sections — this species has needs that are easy to underestimate.