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Variety of Oscar

Red oscar

Astronotus ocellatus

One of 4 varieties of Astronotus ocellatus · See all varieties →

FreshwaterFish

Red oscar (Astronotus ocellatus)

Varieties · Astronotus ocellatus

See all 4 →

Care at a glance

Temperature
68–82°F
20–28°C
pH
6.0–7.5
Adult size
13.8 in
35 cm
Minimum tank
75 gal
284 L
Temperament
Aggressive
Social behavior
Solitary
Tankmates
With caution
Swim level
Middle
Diet
Carnivore
Difficulty
Medium
Breeding
Substrate spawner · Hard
Rarity
Rare
Family
Cichlidae

Overview

The red oscar carries orange-red across most of its flank, with the dark base pushed back to the head, back and fins. Its color deepens as it grows, and juveniles on sale are usually much duller than the adults they become. It is a moderately demanding fish to keep.

Did you know

The red oscar never actually loses its dark pigment. Oscars can shift their coloring quickly, a trait tied to territorial displays and disputes. On a red fish, that shows up as dark blotches surfacing across the flank, then fading again.

Caring for the red oscar

Give a single adult red oscar at least 75 gal (284 L). It rearranges its tank, so use a sandy floor and secure decor. A few large pieces of driftwood and rounded rocks give it cover. Plants usually get uprooted, so pot sturdy ones or leave them out.

Keep it in soft to neutral water, at 68 to 82°F (20 to 28°C) and a pH of 6.0 to 7.5. It eats heavily and makes a mess, so run strong filtration and do regular large water changes. Feed a quality cichlid pellet as the staple, with prawn, mussel and earthworm as occasional extras. Avoid a diet of feeder fish or plain mammal meat.

Keep it singly or as a bonded pair, alone or with big, sturdy tank mates. It is predatory and territorial, swallows any fish small enough to fit in its mouth, and can bully companions. Anything kept with it must be too large to eat and able to hold its own.

It is a substrate spawner, and a pair cleans a flat rock and guards the eggs and fry. Breeding is hard, mostly because of the fish's size and the difficulty of pairing. The red is graded rather than on or off, so spawns come out uneven and get sorted for coverage.

Good to know

Red is a selection on how much orange-red pigment a fish carries and how far it spreads, not a single named gene. Coverage varies between suppliers and between fish in the same shop tank, so buy by eye rather than by the label.

In the wild

The red oscar's solid red flanks do not occur in wild fish. The line was fixed on ornamental farms by breeding from fish with unusually heavy red marbling, and it is now standard trade stock. Hobby accounts credit a Thai breeder who picked unusually red fish out of a late-1960s shipment. That story is repeated more often than it is documented, so treat the origin as uncertain.

From published sources

Tank mates

Each fish here is named as a tank mate for the red oscar by at least two published care guides. Fishkeeping World and Imperial Tropicals recommend keeping it on its own instead. Add tank mates at adult size, since an oscar eats any fish that fits its mouth. The tank needs more than the oscar's own 75 gallons (284 liters).

Sources: Aquarium Co-Op, Fishkeeping World, Aquarium Source, Practical Fishkeeping, Seriously Fish, FishLab.

Check the full mix in the stocking calculator

Common questions

Is a red oscar a different species from the oscar?

No. A red oscar is a variety of the oscar, Astronotus ocellatus, and it wants the same tank, water and food as the species.

What size tank does a red oscar need?

A red oscar needs at least 75 gal (284 L). It spends most of its time in the middle.

What does a red oscar eat?

A red oscar eats a quality cichlid pellet as its staple, with prawn, mussel and earthworm as occasional extras. Feeder fish and plain mammal meat should not make up its diet.

How big does a red oscar get?

An adult red oscar reaches about 13.8 in (35 cm).

How does a red oscar breed?

Red oscars are substrate spawners, and a pair cleans a flat rock and guards its eggs and fry. Pairing them is difficult, and spawns come out uneven, so the young get sorted for red coverage.

What fish can live with the red oscar?

Published care guides name leopard sailfin pleco, silver dollar, common pleco and silver arowana, among others. Add tank mates at adult size, since an oscar eats any fish that fits its mouth. The tank needs more than the oscar's own 75 gallons (284 liters).

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