The Sea Apple, Pseudocolochirus violaceus, is also known as the Violet Sea Apple, Violet Sea Cucumber, and Violet Sea Urchin. It should only be cared for by an experienced aquarist as it can release a potent toxin when stressed or injured that can affect other species in the tank - it should also be handled with caution. It must be introduced into a well-established tank with plenty of space to move around, a moderate waterflow, live rock and a sandy substrate, and copepods to feed on. They are sensitive to light and water quality fluctuations as well as predators that may pick on it.
The Sea Apple should be fed liquid foods of brine shrimp, grated mussel, or other carnivorous preparations at least three times per week. If you notice an oily residue on the surface of the acclimation container, find cucumber floating on top of the water, any cloudiness in the bag, or note that the acclimation water is very discolored do not add cucumber or acclimation water to the aquarium. It is important to be cautious in caring for the Sea Apple as it can have adverse effects if done improperly.