Need help to ID growth on crabs back


Premium Member
Hi All,

Does anyone know what these cone like growths are on the back of one of my Cortez Red Legged Hermit crabs. While you cannot see it in the photo, there is a white feathery leg or arm that extends out of the bottom cone and keeps moving back and forth while the crab moves around. It doesn't seem to be hindering the crab at all.

Any help would be appreciated.



Premium Member
They're barnacles, which are a weird type of filter-feeding crustacean. You don't see the feeding appendages of the top one because it's dead.