Yellow Cubicus Boxfish (Ostracion cubicus)

Care Level - Expert

Temperament- Semi-aggressive

Reef Safe - with Caution

Max Size - 1'6"

Min. Tank Size - 125 gallon

The Cubicus Boxfish is also referred to as the Yellow Boxfish, Polka Dot Boxfish, or Cube Boxfish. The juvenile form is easily identifiable as having a yellow box-shaped body with brown spots. As an adult, the yellow will fade and become brown. The Cubicus Boxfish is sometimes confused with the Longhorn Cowfish, Lactoria cornuta which is occasionally also called the Yellow Boxfish.

This is a very difficult fish to keep in the aquarium setting by any other than the most experienced aquarist. It should have a minimum of a 125 gallon tank. Use caution if placing the Spotted Boxfish in a reef tank as they will often nibble at tubeworms. If stressed, the Cubicus Boxfish releases a poisonous substance, called ostracitoxin, from its mucous glands which will kill other fish in the tank very quickly.

Very little success has been achieved in breeding these fish in an aquarium.

When first introduced, the Cubicus Boxfish prefers a diet of live brine shrimp or bloodworms. Once acclimated, the diet should include chopped squid, clams, mussels, and herbivore preparations.

Approximate Purchase Size: Tiny: 1-1/2" to 2-1/4" Small: 2-1/4" to 3"; Medium: 3" to 4; Large: 4" to 5"