Scarlet Hermit Crab

The red reef hermit crab, scientifically known as Paguristes cadenati, is a small marine decapod crustacean native to the tropical reefs of the Caribbean Sea and western Atlantic Ocean. Reaching a modest average size of 1 to 1.5 inches (2.5 to 3.8 centimeters) in length, it is easily recognized by its vibrant, solid bright red or scarlet coloration on its body, legs, and claws, paired with distinct yellow or white eyestalks. These hermit crabs are prized clean-up crew members due to their diligent scavenging habits and small, reef-safe size. They spend their time continuously foraging across live rock, sand beds, and coral rubble, picking away at nuisance hair algae, cyanobacteria, detritus, and uneaten fish food. Because their claws are equal in size and relatively small, they are far less destructive to sessile invertebrates and corals than larger or more aggressive hermit species.

In a home saltwater aquarium, Paguristes cadenati is peaceful, low-maintenance, and compatible with almost all non-predatory tank mates. Like all hermit crabs, they require a supply of slightly larger empty snail shells scattered throughout the aquarium so they can safely molt and transfer to new homes as they grow. Providing adequate replacement shells also prevents them from harassing living ornamental snails for their housing.