Ocellaris Clownfish

Overview

The Ocellaris Clownfish (Amphiprion ocellaris) is the classic 'Nemo' clownfish, hardy and a great first marine fish. It is a popular choice among Australian aquarists, reaching around 8 cm and living roughly 6-10 years when properly cared for.

This complete guide covers how to keep the Ocellaris Clownfish successfully - tank size and setup, water parameters, the best foods (including recommended brands), suitable tank mates, breeding, sexing and the health issues to watch for. It is rated Beginner to care for.

Natural Habitat & Origin

This is a saltwater species from tropical coral reefs. It requires a stable, mature marine aquarium with correct salinity (around 1.024-1.026), excellent filtration and pristine water.

Matching the temperature, water chemistry and cover a species evolved with is the simplest route to keeping it healthy and seeing its natural behaviour and colour.

Tank Size & Aquarium Setup

Provide a minimum of 75 litres for the Ocellaris Clownfish. A roomy, well-decorated tank lets a pair settle and behave naturally.

Live plants, driftwood and shaded retreats give security and show off the fish's colours against a natural backdrop.

Always add fish only to a fully cycled, mature tank with stable biological filtration. Match filtration generously to the fish's size and waste output.

Water Parameters

Keep the Ocellaris Clownfish in stable water at 24-27 °C with a pH of 8.1-8.4. It prefers harder, alkaline water, which matches much of Australia's tap supply.

Test regularly: ammonia and nitrite must read zero, and nitrate should be kept low with routine partial water changes. Always dechlorinate and temperature-match new water, because sudden swings cause far more illness than water that is stable but slightly imperfect.

Diet & Feeding

The Ocellaris Clownfish is an easy-going omnivore that accepts a wide range of foods.

In Australia, good options include Hikari Marine and Dymax frozen marine foods such as mysis and brine shrimp (note the mandarin dragonet needs a mature tank full of live copepods). Feed small amounts once or twice a day (only what is cleared in a minute or two), vary the diet for the best colour and health, and avoid overfeeding, which is the leading cause of poor water quality.

Temperament & Tank Mates

The Ocellaris Clownfish is semi-aggressive: generally community-tolerant but territorial at times, especially when breeding or under-stocked. Avoid very small, slow or long-finned tank mates and give everyone space.

Breeding

The Ocellaris Clownfish is an open substrate spawner that pairs off and lays eggs on a cleaned rock or leaf, with both parents fiercely guarding the eggs and fry.

Even if you are not planning to breed it, recognising this behaviour helps you understand what you are seeing and respond well - for example by adding cover for fry or giving a guarding pair extra space.

How to Tell Males from Females

Sexing depends on the species; some change sex, others show size or colour differences only when paired.

Common Health Problems

Marine fish are prone to marine ich (Cryptocaryon) and velvet; quarantine new arrivals and keep salinity and water quality rock-stable. Quarantine new arrivals for 2-4 weeks and watch daily for early signs such as loss of appetite, unusual hiding, clamped fins or laboured breathing - caught early, most issues are very treatable.

Prevention beats cure: keep water pristine, avoid overstocking and overfeeding, quarantine new arrivals, and act at the first sign of trouble.

Is the Ocellaris Clownfish Right for You?

The Ocellaris Clownfish suits beginners and experienced keepers alike, as long as you can provide at least 75 litres, water at 24-27 °C and pH 8.1-8.4, the right diet and suitable tank mates.

Meet those needs and the Ocellaris Clownfish will reward you for around 6-10 years. Use our free aquarium calculators to plan your setup, and explore our other fish, plant and disease guides to build a thriving aquarium.

Frequently Asked Questions