Red Claw Crab Care Guide - Habitat, Diet & Breeding Notes

The Red Claw Crab, Perisesarma bidens, is a small mangrove crab with a dark purple-brown to reddish carapace and conspicuous red-orange claws, particularly in mature males. Its compact body and stalked eyes give it the familiar appearance of a true shore crab, while the flattened walking legs help it move across mud, roots and shallow water.

Red Claw Crabs are native to mangrove forests, tidal creeks and estuarine wetlands across parts of Southeast Asia, including Indonesia, Malaysia, Singapore, Thailand and the Philippines. They inhabit the boundary between land and brackish or marine-influenced water.

A single Red Claw Crab needs at least a 60-litre paludarium, with a larger footprint—ideally around 60 × 30 cm or more—preferred over a tall aquarium. The enclosure should include a substantial land area with secure access to shallow, filtered brackish water; these crabs cannot live permanently submerged. Use sand or fine mud-compatible substrate, sturdy driftwood, rocks, mangrove-style roots, caves and robust plants, and fit a tight lid because they are capable climbers. Keep the land section humid and ensure all décor is stable and escape-proof.

Adults reach approximately 5 cm (2 in) across the carapace, excluding the legs and claws. Males are usually slightly larger and have noticeably larger claws than females.

These opportunistic omnivores should receive a varied diet of sinking crab or shrimp pellets, algae wafers, blanched vegetables and occasional meaty foods such as frozen bloodworm, brine shrimp or small pieces of seafood. Fallen mangrove leaves and other safe vegetable matter can provide useful grazing material. Remove uneaten food promptly to protect water quality.

Red Claw Crabs are best kept in a species-focused paludarium because they can be territorial and may catch slow, resting or bottom-dwelling tankmates. They are generally unsuitable for community aquariums, where they may prey on small fish, shrimp and snails or be harassed by larger fish. If several are kept, provide ample space, hiding places and more females than males; adult males may fight.

Breeding Red Claw Crabs in captivity is difficult. Females carry eggs beneath the abdomen, but the larvae hatch into the water and require marine conditions, specialised planktonic foods and carefully managed rearing facilities before they can develop into young crabs. Most specimens in the aquarium trade are wild-caught rather than captive-bred.

Males generally have larger, brighter red claws and a narrower, more pointed abdominal flap. Females have a broader, rounded abdominal flap for carrying eggs and usually smaller claws.