These sedentary creatures are often regarded as beautiful and desirable invertebrates for the reef aquarium; but beware, there can be a high price to pay! Large polyps of this nature are highly predatory on fish and crustacea.
The subject will often rest on the polyp disc while it closes about them like a football. From this spherical prison there is no escape, for the animal will be killed, passed through the central mouth and digested. Many unwitting marinists have lost hawkfish, mandarins, shrimp, blennies and gobies to this 'disc of death', with little, or no trace of the body.
Fortunately, this is not a job for the X-Files and the solution is simple. The offending polyp must be removed and re-located back to the aquarium store!
© Nick Dakin. May not be reproduced in part, or whole, without permission.