Ah, this may explain their difficulty in tanks.
As aquarium residents, sea slugs as a group vary greatly in their suitability for captive life. In most cases, the problem is that sea slugs are typically extremely specialized feeders. Many of the nudibranchs feed only on a particular species of cnidarian, sponge, bryozoan, or tunicate, for example.
Berghia verrucicornis, the nudibranch that is now bred in captivity and marketed as a control for Aiptasia anemones in reef tanks, feeds only on this genus, and can only be maintained when this anemone is present in the tank. The specific organisms fed upon by other nudibranchs are often difficult or impossible to raise in captivity. In the case of the sacoglossan sea slugs, the particular algae that a given species of
sea slug feeds upon must be present. Different sources cite different algae as the preferred foods of lettuce sea slugs, with various
Caulerpa species as well as a number of other species of
green algae typically being named (Kaplan 1982, and
www.seaslugforum.net). In the aquarium trade, lettuce sea slugs are marketed as control agents for
Bryopsis, though Delbeek and Sprung (1994) suggest that only certain color forms will feed on
Bryopsis (see
www.seaslugforum.net for photos of some of the different color forms).
Sir Royal Master Cody William Deuter the 3rd
