Gastropod of some sort. Small limpet-like shell (~3/8"), animal has B/W antennae and a long black protrusible forked tongue. From what I know, true limpets have a rasping radula so this is something entirely different. In the 4 months that I've had it in my tank, it has never moved from the shown position on the hermit's cone shell. The 'tongue' seems to probe the rock and sand whenever it can reach them.
Any ideas?
Any ideas?