Few mollusks are found in aquariums, and they are not often available commercially.
Among the gastropods, the cowries, well known to collectors of shells, can be kept
in captivity. Some fish may nibble the "mantle", the part of the animal's body used
outside the shell.
Shrimps play an ecological role by feeding on fishes' leftovers.
Of course, in the event of any danger the animal retreats into its shell. Hobbyists
enchanted by the beauty of this shell can put a specimen in a tank containing small
Pacific fish (Gobiids, Blenniids, Grammids. Pseudochromis, for example). In the
bivalve group there is the famous giant clam, which can sometimes grow up to a length
of 1 m in the wild, where it feeds on vegetal plankton. Some smaller species can
be acclimatized in an aquarium. However, these animals are only recommended for