A bivalve wedged in a crevice with a fringe of red tentacles showing. Unlike the electric flame scallop of the Indo-Pacific it does not produce a running light.
Shell 5 to 9 cm. Two ribbed, roughly sculptured, off-white to brownish valves, usually hidden in a crevice. What you actually see is a brilliant scarlet mantle fringed with a dense curtain of long red and white tentacles protruding from the gap between the shells. The red comes from carotenoid pigment.
It is not a scallop. It is a file clam, in a different family, and “flame scallop” is a long-standing misnomer; the proper name is the rough file clam.
The Indo-Pacific electric flame scallop is the one it is compared with, and that animal shows a rippling flashing line along the mantle edge, which this one does not. A second Caribbean file clam has a smoother shell and shorter tentacles.
It filters plankton and detritus from the water. It lives wedged in reef crevices, under ledges and inside coral rubble between about 1 and 40 m, often building a nest of shell and rubble fragments bound together with its own threads, so look into holes and under ledges rather than on open reef. It can swim by clapping its valves to escape crabs and shrimp.
It is collected heavily for the aquarium trade, where it almost always starves.
Ratings are per location: 1 means found on most dives that look for it, 5 means a handful of records. Where enough dives have been logged the figure is calculated from them; otherwise it is an editorial estimate, and says so. We publish habitat and destination, not the dive site.