Red claw crab (Perisesarma bidens) care guide
- Group
- Other invertebrates
- Other names
- Red-clawed crab, Red claw mangrove crab, Sesarma bidens, Chiromantes bidens, Grapsus bidens
- Family
- Sesarmidae
- Origin
- Indo-Pacific, from Zanzibar east to Japan and Fiji
- Water
- brackish
- Maximum size
- 5 cm
- Care level
- intermediate
- Temperament
- semi_aggressive
Care
The red claw crab is a small Indo-Pacific crab named for its bright red claws, often sold in shops as a 'freshwater' crab. Its carapace usually stays under about 5 cm, with a leg span up to about 10 cm. It is not a crayfish, so the UK crayfish sale rules do not apply to it. Our sources have little on this species; the figures are general guidance, not from a source. It is a semi-land crab of mangroves and estuaries, so it does best in a brackish paludarium: shallow, slightly salty water (a low specific gravity), plus a land area of sand, roots or rock where it can climb out and rest. Kept fully submerged in a normal tropical tank it may drown or decline. A warm tropical temperature in the low to mid 20s °C suits it. A tight lid is essential; it is an escape artist and will climb pipes and cables. It is active, mostly at dusk and night, and territorial. Keep one male per tank, or a male with females, with plenty of hiding places to reduce fighting. It moults as it grows and hides until the new shell hardens. Copper-based medicines and some plant fertilisers are toxic to shrimp, snails and most invertebrates. Sources: Wikipedia (en.wikipedia.org/wiki/Perisesarmabidens). Checked October 2026.
Diet
General guidance, not from a source: an omnivorous scavenger that eats leaf litter, plant matter, algae and any animal food it can catch or find. Feed sinking pellets, blanched vegetables, frozen bloodworm, prawn and fish, and dried leaves.
Breeding
General guidance, not from a source: females carry eggs under the broad abdominal flap, while males have a narrow flap and larger claws. The eggs hatch into tiny larvae that need full-strength or near sea water and plankton foods to develop, so breeding in captivity is very rarely achieved.
Compatibility and tank mates
General guidance, not from a source: not a community crab. It will catch small or sleeping fish, eat shrimp and snails, and fight other crabs. Fish that stay in mid-water and tolerate brackish water, such as mollies or bumblebee gobies in a separate area, can sometimes be tried in a large set-up, but it is best kept in a species paludarium.
Last updated 8 October 2026. Community-edited care guide on Aquatic-Auctions.