圆顶蟹是一种圆顶状外壳的珊瑚礁蟹，也称红蟹，而斑马蟹是一种微小的海胆蟹，其白色身体有深棕色条纹，腿上

pback crab is generally red or reddish in color, sometimes beige or brown, with irregular darker spots; a central dark spot often features two small white dots resembling a mask or a skull. It lives in coral reefs and shallow rocky areas at depths between 2 and 60 meters, hiding in crevices during the day. As for the zebra crab, it belongs to the crustacean family and lives in very close association with sea urchins, particularly venomous ones such as the fire urchin. It measures about 2 to 3 cm wide, with a carapace that can reach 25 mm. It has vertical brown or reddish-brown stripes on a white background, with an angular body, horns near the eyes, and serrated legs adapted for life on the sea urchin. In juveniles, these horns and teeth are less pronounced. It is a symbiotic crab that lives on sea urchins and feeds on their tissues; it generally remains alone on a host. Its most remarkable trait is its ability to live on poisonous sea urchins, making it a highly specialized crab that is easily recognizable to divers. It generally lives at depths of 5 to 20 meters, on sandy, muddy, or detrital bottoms, or in seagrass beds.