Common name: Trapeziid crabs

Trapeziidae, commonly known as Trapeziid or Quadrate crabs, are a family of small crabs that often form symbiotic relationships with reef-building corals. They are known for their protective role, as they defend their coral hosts from predators and harmful parasites. In return, they receive shelter and food in the form of mucus and detritus from the coral. These crabs are generally reef-safe and can be beneficial in a home aquarium by promoting coral health. They are small, typically less than an inch in size, and exhibit a range of colors that often blend with their coral hosts, making them an interesting addition to a reef tank.