Red Clawed Crab

Red Clawed Crab

12/04/2021 Off By Andy Ptyushkin

Red Claw Crabs are classic brackish water, mangrove crabs. They have lot of character, personality, and can be a great addition to your home tank. The only rule here is that they are not fully aquatic. Red Claw Crabs can spend half of their time inland. This is absolutely crucial for their breathing.

Red Claw Crabs are also known as and sometimes sold under the names Perisesarma Bidens, Mini crab, or Sesarma Moeschi. This species of crab is native to Asia where they dwell and thrive in the shallow and warm coastal mangrove swamps. While they are mistaken for freshwater crabs and they can survive in freshwater, they do their best in brackish water.

The shallow mangrove swamps where they are found often mix with the seawater, which raises the salinity. This is where the misconception that they are freshwater crabs comes from. In general, mangrove swamps are freshwater swamps and not brackish, but because the ones where Red Claw Crabs are found are along the coastline, the water will always have some salinity.

Asian mangrove swamp

Asian Mangrove

Red Claw Crabs vary in shades of red, to flaming orange. Their shells are covered in brown spots. The males tend to be brighter and more colourful than females. The tips of the claws will be a yellowish colour, ranging in shade from pale to bright.

The carapace of an adult Red Claw Crab only grows to about 1.5 – 2 inches long (3.5 – 5 cm), with a leg span up to 4 inches (about 10 cm). They are smaller than most aquarium crab species. This is the reason they are sometimes known as Mini crabs.

Red Claw Crabs have two «teeth» (lat. bidēns – having two blades or teeth) on the lateral sides of the carapace.

Red Claw Crabs have a gill chamber (not lung). The gill chamber is located under the carapace near the first pair of walking legs. As long as their gills stay moist, they can be out of the water.

Red Claw Crabs have special plates, that keep their gills moist by shutting the opening in the exoskeleton so that dry air cannot get in. Although they have a gill, they are still semi-aquatic and require fresh air as well.

The average lifespan of Red Claw Crabs in captivity is about 2 years. However, some individuals do live longer. According to the studies, the lifespan of Red Claw Crabs in the wild is about 2.5 years.