Common name: Decorator Crab

General Information

The Decorator Crab, Camposcia retusa, is a fascinating and unique addition to marine aquariums. Known for its intricate camouflage, this crab uses materials from its surroundings, such as algae, sponges, and even small pieces of coral, to decorate its body. This behavior not only helps it blend into its environment but also makes it a visually intriguing species for hobbyists.

Native to the Indo-Pacific region, this crab is often found in coral reefs and rocky substrates. Its spindly legs and body give it a spider-like appearance, which, combined with its decorations, makes it a master of disguise. While not as commonly seen in the trade as other crabs, its unique behavior and appearance make it a sought-after species for advanced aquarists.

Care

Camposcia retusa requires a well-established aquarium with plenty of live rock and hiding spaces. These crabs are nocturnal and prefer to stay hidden during the day, becoming more active at night. They are best suited for tanks with a mature ecosystem, as they rely on natural detritus and algae for sustenance.

While hardy, they are sensitive to poor water quality, so maintaining stable parameters is crucial. A tank with moderate flow and a variety of textures, such as rocks and corals, will help them feel secure and allow them to exhibit their natural decorating behavior.

Diet and Feeding

Decorator Crabs are omnivorous scavengers, feeding on detritus, algae, and small invertebrates. In captivity, they can be offered a diet of algae wafers, frozen foods like mysis shrimp, and finely chopped seafood. They will also graze on algae and other organic matter in the tank.

Feeding should be done sparingly, as they are efficient scavengers and can often find enough food in a well-maintained aquarium. Overfeeding can lead to water quality issues, so monitor their intake and adjust accordingly.

Behavior and Compatibility

Camposcia retusa is generally peaceful but can be opportunistic. It may prey on small, slow-moving invertebrates or fish if given the chance. Care should be taken when housing them with delicate species, as their decorating behavior might involve snipping off pieces of coral or other tank inhabitants.

These crabs are solitary and do not require companions. In fact, housing multiple individuals in the same tank can lead to territorial disputes. They are best kept in tanks with peaceful tank mates that won't harass them.

Symbiosis

While not involved in a specific symbiotic relationship, the Decorator Crab's behavior of using its environment for camouflage is a fascinating example of mutualism. By attaching algae or sponges to its body, it gains protection from predators, while the attached organisms benefit from increased mobility and exposure to nutrients.

Health and Common Issues

Decorator Crabs are relatively hardy but can be susceptible to poor water quality and sudden changes in parameters. Regular water changes and stable conditions are key to their health. When molting, they are particularly vulnerable, so ensure they have plenty of hiding spaces to retreat to during this time.

When selecting a Decorator Crab, look for active individuals with intact legs and claws. Avoid crabs that appear lethargic or have visible damage, as these could be signs of stress or illness.

Habitat

In the wild, Camposcia retusa is found in coral reefs and rocky substrates throughout the Indo-Pacific region. They prefer areas with plenty of hiding spots and a variety of materials for decoration. Replicating this environment in captivity will help them feel secure and exhibit their natural behaviors.