Identification: trapezoid carapace, white to pink, covered in 100 to 200 red or orange spots; green eyes; a pair of large flattened claws and four pairs of walking legs. Wikipedia gives up to about 5 cm in width; Quality Marine describes trade Trapezia as barely over 2.5 cm. When approached, it retreats into the branches with claws raised.
In the wild it is widespread in the Indo-Pacific, from East and South Africa to Hawaii, Polynesia and southern Japan, on coastal reefs and lagoons at 0 to 30 m. It lives deep among the branches of Stylophora and Pocillopora: a small colony hosts one pair, a large one up to five pairs of Trapezia. It massages the coral with its legs to release mucus, which it gathers with the setae of its legs. Trapezia crabs are well-documented defenders of their corals against the Acanthaster starfish; in Polynesia, the small species also defend their host against small coral predators (McKeon & Moore, 2014).
Reproduction: the sexes are separate; courtship is often triggered by smell or touch, the female carries the eggs until planktonic larvae hatch, and the pair then stays in the same colony. No source consulted describes captive breeding.
Status: the species has not been evaluated by the IUCN and is not listed by CITES. It is rarely collected on purpose: it mostly arrives with the corals that host it.
