Red disc, red arm tips, a beaded margin, and prey for the harlequin shrimp.
A small, flat, five-armed sea star to about 10 cm across, and the colour pattern is the identification: the disc is deep red to red-orange, the arm tips are the same red, and the length of arm in between is pale cream to orange-buff. The surface is made of large, regular, slightly domed plates with the marginal plates along each side conspicuously enlarged, which gives the edge of the animal a beaded look and the species its name. Colour intensity varies and the pale mid-arm section can be almost white or strongly orange. The confusion is with the other Fromia — F. indica and F. milleporella are more uniformly red and finely dotted with dark pores — and with Linckia multifora, which has narrow cylindrical arms rather than flat plated ones.
It is an animal of hard substrate rather than open sediment, so on a muck site it is on the rubble edges, sponge-covered rock and reef slope, moving in the open by day as well as at night. It grazes sponges, encrusting material and the microbial film on rock. It is also food: Fromia is one of the sea stars the harlequin shrimp Hymenocera picta takes most often, and a pair of harlequins is frequently found in a rubble hollow with a necklace sea star being eaten arm-first over several days, so a Fromia with one arm chewed short is worth looking under the rocks around it. Sea stars of this genus also carry Zenopontonia soror on the oral surface, though less reliably than the larger species do.
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.