Bristly Crab (Pilumnus hirtellus) – Complete Care Guide

General Information

The Bristly Crab or Hairy Crab, scientifically known as Pilumnus hirtellus, is a small, hardy crab species that is often found in rocky intertidal zones and shallow waters. Its common name derives from its distinctive bristly or hairy appearance, with its carapace and legs covered in fine setae that help it blend into its surroundings. This camouflage makes it a fascinating addition to marine aquariums, particularly for hobbyists interested in creating a naturalistic setup.

While not as popular as some other crustaceans in the aquarium trade, the Bristly Crab is appreciated for its unique appearance and its role as a scavenger. It is a relatively small species, making it suitable for nano tanks or as part of a larger community setup. However, its secretive nature means it may not always be visible, as it tends to hide among rocks and crevices during the day.

Care

The Bristly Crab is a hardy species that adapts well to a range of aquarium conditions. It thrives in tanks with plenty of live rock and hiding spots, which mimic its natural habitat. These crabs are nocturnal and will often emerge at night to scavenge for food, so providing a dimly lit or moonlit environment can encourage more natural behaviors.

While generally easy to care for, the Bristly Crab can be territorial and may show aggression towards other small crustaceans or slow-moving tank mates. It is best kept in a species-specific tank or with compatible, non-aggressive tank mates. Regular water changes and stable water parameters are essential to its health and longevity.

Diet and Feeding

In the wild, the Bristly Crab is an opportunistic scavenger, feeding on detritus, algae, and small invertebrates. In captivity, it will readily accept a variety of foods, including sinking pellets, algae wafers, and frozen or live foods such as brine shrimp and mysis shrimp. Supplementing its diet with marine algae or seaweed can help maintain its health and coloration.

Feed the Bristly Crab once or twice daily, offering only as much food as it can consume within a few minutes. Overfeeding can lead to water quality issues, so monitor its intake and adjust portions as needed.

Behavior and Compatibility

The Bristly Crab is generally peaceful but can be territorial, particularly towards other crabs or small invertebrates. It spends much of its time hiding among rocks and crevices, emerging primarily at night to forage. This nocturnal behavior makes it an interesting, albeit elusive, addition to the aquarium.

While it is not considered reef-safe, the Bristly Crab can coexist with certain hardy corals and fast-moving fish. However, caution is advised, as it may nip at soft corals, polyps, or slow-moving tank mates. Providing ample hiding spots and a well-structured tank can help minimize territorial disputes.

Health and Common Issues

The Bristly Crab is a hardy species with a lifespan of several years in captivity when provided with proper care. Maintaining stable water parameters, a balanced diet, and a clean environment are key to its health.

When selecting a Bristly Crab, look for active individuals with intact appendages and a healthy, bristly appearance. Avoid crabs that appear lethargic or have visible signs of damage or disease. Regular water changes and monitoring for signs of stress or illness can help prevent common health issues.

Habitat

The Bristly Crab is native to the northeastern Atlantic Ocean, including the coasts of Europe and the Mediterranean Sea. It is commonly found in rocky intertidal zones, tide pools, and shallow subtidal areas, where it hides among rocks and algae.

This species prefers habitats with plenty of hiding spots, such as rocky crevices, algae-covered surfaces, and areas with moderate water flow. Replicating these conditions in captivity can help ensure its comfort and well-being.

Common name: Bristly Crab