"The Carpet Anemones are named for their immense size (sometimes more than a meter/yard across) and "pile" of numerous colored tentacles. These are unfortunately very difficult aquarium specimens that "shed", otherwise can/do sting and poison tankmates. Unless you have a HUGE system (hundreds plus gallons of water) and/or a substantial sized system to dedicate to just this one animal (plus possibly host fishes), you are advised to look elsewhere for an anemone species.
Of the three species of Carpets that are commensal/symbiotic with Clowns (and the Three-spot Damsel), only H. mertensii has good potential for being kept in a "mixed reef" setting... the other two species are found anchored in sand... with no other Cnidarians w/in physical or easy-chemical reach."
Copied from article by Bob Fenner.