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crabmediumFreshwater

Red Claw Crab

Perisesarma bidens

📍 Southeast Asia (Thailand, Malaysia, Indonesia)

Ask Finn

The Red Claw Crab is a semi-aquatic species native to Southeast Asia, recognizable by its distinctive red claws and compact body. These crabs are moderately aggressive and require both aquatic and terrestrial zones in their tank setup. They are popular in the hobby but demand careful tank mate selection and specific environmental conditions.

Size2"
Min Tank20g
semi-aggressive
Zonebottom

Care Guide

Diet

Red Claw Crabs are opportunistic omnivores that consume algae wafers, blanched vegetables (spinach, zucchini), small invertebrates, and biofilm. Supplement with quality sinking pellets and occasional live or frozen foods like bloodworms or brine shrimp. Feed small amounts 2-3 times per week, removing uneaten food after 24 hours.

Behavior

These crabs are primarily nocturnal and spend much of their time foraging on the substrate and climbing on décor. They are territorial and will fight with conspecifics and may prey on smaller tank mates or shrimp. They require access to both water and land; provide driftwood, rocks, or a floating platform for emergence and resting.

Breeding

Breeding in captivity is extremely difficult and rarely successful in home aquariums. Females produce larvae that require brackish water to develop, making freshwater breeding impractical. Most specimens in the hobby are wild-caught or commercially bred in specialized facilities.

Common Diseases

Shell Erosion / Molt Issues

Symptoms

Soft or pitted exoskeleton, difficulty molting, lethargy, loss of limbs

Treatment

Ensure adequate calcium and minerals in water; provide cuttlebone or calcium supplements; maintain proper pH and hardness; ensure proper humidity in terrestrial zone

Bacterial Infection / Fungus

Symptoms

White or fuzzy growth on body or claws, discoloration, lethargy, loss of appetite

Treatment

Perform 25% water changes; improve water quality and tank hygiene; isolate if possible; use aquarium salt (1 tsp per gallon) or antifungal treatment; ensure adequate aeration

Parasitic Infection (Flukes, Mites)

Symptoms

Excessive scratching, visible parasites on body, lethargy, difficulty molting

Treatment

Quarantine affected crab; treat with appropriate parasite medication; perform frequent water changes; improve tank conditions; avoid copper-based treatments

Limb Loss / Autotomy

Symptoms

Missing claws or legs, bleeding or open wounds

Treatment

Isolate injured crab to prevent further injury from tank mates; maintain pristine water quality; provide protein-rich foods to support regeneration; limbs will regrow over successive molts

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Quick Facts

diet
omnivore - detritivore with carnivorous tendencies
lifespan
2-3 years
max size
5 cm (2 in)
tank size
20 gallons minimum
temperament
semi-aggressive

Water it likes

ph
6.5-7.5
ammonia
0 ppm
nitrate
<20 ppm
hardness
4-8 dGH
temperature
72–79°F (22–26°C)

Stats

Community tips0
Kept by0 hobbyists