Common names for the Ocellaris Clownfish include; Clownfish, Common Clownfish, False Clownfish, Anemonefish, Ocellaris and of course, Nemo.

Pair of Clownfish
Pair of Clownfish

Made popular by the films Finding Nemo & Finding Dory, the Ocellaris Clownfish is one of the hobby’s favourite fish. This fish makes an excellent addition to most aquariums, but care should be taken when adding different morphs of the clownfish to your aquarium as some have been known to be aggressive.

Clownfish have the ability to change sex, the bigger more dominant one will be the female. Once they become a mated pair, it will be difficult to add any other clownfish to your tank as they will become territorial, so you should add all the clownfish you are planning on keeping in one go. They should also all be of a similar size to reduce aggression.

The Ocellaris Clownfish is widely considered the least aggressive of the Clownfish species, some reefers have reported some of the more collectible species to be aggressive toward humans, but not often aggressive towards fish.

It is considered normal clown behavior for the female of a pair to “beat up” the male initially to establish dominance.

It is possible for different species of Clowns to pair up, but this should not be expected, rather considered an exception to the rules.

Tank Requirements & Facts

  • Minimum tank size: 20 Gallon (90 Litres)
  • Prone to disease: No
  • Beginner Compatible: Yes
  • Adult Size: 3 inches (7.6cm)
  • Reef Compatible: Yes
  • Predator Tank Compatible: No
  • Care Level: Easy
  • pH: 8.1 to 8.4
  • Temperature: 22°C to 27°C
  • Preferred Tank Level: Any
  • Number to a tank: Can be kept in mated pairs, hareems or alone.
  • They can form a symbiotic relationship with an anemone where the clown will feed the anemone in return for protection & parasite removal.


  • These are omnivores
  • They have been known to take food to their anemone to feed it
  • They are aggressive eaters and will eat most things put into the tank
  • They don’t tend to graze on Nori
  • Flaked food, frozen food & live foods are readily accepted


When acclimating your clownfish it is best to do so in a deep bucket that the fish is unable to jump out of.

Place your fish in the bucket and then drip acclimate for about 45 minutes at a rate of 3 drips per second. This should bring the fishes water parameters in line with your tanks parameters.

Once your fish has been drip acclimated, catch the fish with a net and place it gently into your tank. Do not put any of the water the fish originally came in, into your tank.

Do I have to have an anemone for my clownfish?

The simple answer to this is no. Many people have great success in keeping clownfish in fish only tanks.

They will host a number of different things, they have been known to host corals such as hammers or torches, they have also been known to try and host clams & plating corals and even the odd powerhead.

Be aware that not every coral will tolerate your clownfish rubbing against them all the time, you may have to try to encourage your clownfish to host elsewhere.


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