This profile was written by Ken Tweddle an active contributor to the site.




Perisesarma (Sesarma) bidens



    The Red Claw Crab is a forager. They use fine hairs on their legs and claws to taste the sand and will spend a large amount of time scavenging the substrate for food. These crabs like to make small tight fitting caves under rocks and logs and will quickly scurry to safety when threatened. They also spend a few days in their burrows during molting and should not be disturbed during this process. There should be a place above the waterline such as a pile or rocks, wood or other substrate so the crab can climb out of the water. The Red Claw Crab is a good climber and will go exploring outside of your tank if it finds a way out. Run air tubes and power cords through small holes in your hood and keep the aquarium sealed to the best of your abilities.

Quick stats:

Listed tank sizes are the minimum
Size: Leg span up to 4″ (10 cm)
Tank: 10 gal minimum
Strata: Benthic
PH: 7.5 to 8.5
Hardness: dKH 8+
Temperature: 75°F to 80°F (24°-27° C)


Order: Decapoda
Suborder: Labroidei
Family: Sesarmidae
Genus: Sesarma
Species: Bidens


Common name:

Red Claw Crab

    , Thai Crab


    Mangroves and Mudflats of South China Sea From Hong Kong to Singapore.

General Body Form:

    Flattened shell with protruding eye stalks and Two equal sized claws.


    Dull red with brown patterns and bright red claws.


    Best kept in brackish conditions with land access. The addition of Marine Salt in the amount of 2 tbs/gal or a Specific Gravity of 1.005 is sufficient. The use of Marine Grade Salt will help to provide trace minerals needed for proper development. As the crab grows it must shed its exoskeleton. The new shell is soft and the crab will hide for a few days until this hardens. The use of a sand or soil substrate will allow for more natural feeding habits as well as facilitate burrowing. Red Claw Crabs are Omnivorous and enjoy brine shrimp, bloodworms, peas, beans, spinach and raw fish. They will also eat commercial flake foods and crab pellets as well as bits of driftwood and aquarium plants.


    Mangrove swamp or Mud Flats. P.bidens make good companions for Mud Skippers, Knight Gobies Bumblebee Gobies, Indian Glass Fish, Halfbeaks, Mollies, Guppies, Amano and shrimp and other Brackish fish that do not prey on large invertebrates. These types of setups are most easily filtered with canister, or in-tank filtration as Hang On Back types do not work well with lowered water levels. Keep the water well below the rim of the tank and allow for safe perches above the waterline.

Breeding:Special breeding requirements will not likely be met in the home aquarium. Larva of The Red Claw Crab live for a time as Plankton in the water column.


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