Perisesarma bidens Red Claw Mangrove Crab

Perisesarma bidens is a small, boldly coloured sesarmid crab native to Indo-Pacific mangrove and estuarine habitats from India and Sri Lanka through Southeast Asia to Japan and the Pacific. Males are readily identified by their vivid red-tipped chelae, which contrast sharply with the dark brown to olive carapace. Adults reach approximately 2.5–3 cm carapace width.

In captivity, P. bidens thrives in a brackish paludarium that replicates its natural intertidal mangrove environment. A sandy or muddy substrate shoreline sloping up from a brackish water section, with mangrove root and driftwood structures above the waterline, provides the semi-terrestrial access this species requires. Brackish water at low specific gravity — approximately 1.003–1.008 — produces the best results, although some specimens adapt to near-freshwater conditions.

This species is an active forager consuming mangrove leaf litter, detritus, algae, and small invertebrates. In captivity it accepts dried leaves, blanched vegetables, sinking pellets, and dried shrimp. Mixed-sex groups can be maintained in appropriately sized enclosures with adequate shelters. Breeding larvae require full marine conditions.

Water: 20–28°C, pH 7.5–8.5, GH 8–20, KH 4–12; brackish 1.003–1.008 SG; muddy or sandy shoreline substrate. Tank: minimum 50 L paludarium; mangrove roots, sandy slope, brackish water section, leaf litter; secure lid. Feeding: omnivore — dried leaves (Indian almond), blanched vegetables, dried shrimp, sinking pellets; feed every 1–2 days. Breeding: larvae require full marine conditions; captive rearing through larval stage not practical. Compatibility: mixed-sex groups; semi-terrestrial; do not mix with shrimp; incompatible with small fish.