Common Squat Lobsters can sometimes be found as hitchhikers on live rock or corals and make fine pets, but these hitchhikers are normally dull colored. Crinoid Squat Lobsters such as the ones pictured above are becoming more common in the aquarium trade. In the wild, these crustaceans are commensal on Crinoid Feather Sea Stars. They use the sea stars for camouflage and steal their food. 

Crinoid Feather Stars are one of the most difficult echinoderms to successfully maintain in aquariums. Luckily, these Crinoid Squat Lobsters do not require them for survival. They readily accept frozen foods and adapt well to aquarium life."

Unless you find a mated pair, two of the same species shouldn't be kept in the same aquarium as they will fight. 

Approximate Purchase Size: Small: 1/2" to 1"; Medium: 1" to 1-1/2"