Because of their diets, all Linckia need to be in large mature reef tanks with a lot of LR, and there should not be more than one unless the system is very large (over 100g). The do not feed on detritus and are not part of a clean up crew. They feed on microbial and algal films, as well as other encrusting animals like sponges and bryozoans. If they are not in a suitable system, they will tend to starve, a process that takes months up to a year.
The purple Linckia, as it is often called, is not typically a Linckia. If it has orange tube feet, it is a star called Tamaria stria, and potentially not reef safe by some accounts.
All species of Linckia and the similar Fromia(elegant star) are very delicate, and need to be drip acclimated for many hours, at every step of their transport. I recommend this for all echinoderms (seastars, urchins, cucumbers, brittle/serpentstars).
Most other species of brittle or serpentstars are not known to be predatory. However, they should all be spot fed and not allowed to scavenge. They will eat if they are hungry. The green brittlestar is a known predator in the wild, and should never be sold simply as a clean up crew. Most species of brittle/serpents are hardier than Linckia and better suited to smaller and/or younger systems.
. a very costly learning experiance.
