1 kinds · tap one for a closer look
Semi-aggressive; will nip fish.
142 species in our list are a good match.
Semi-aggressive; will nip fish. Needs land.
Not a freshwater tank animal. It needs brackish water or a setup that is mostly land. Read the care notes before you buy.
Good to know: Needs a land area and brackish water.
Algae, small meaty foods and vegetables.
Tap a food to see what it is.
Females have a much wider, oval belly flap (pleon); males have a narrow, pointed one and usually larger, brighter claws.
Common problems. Tap one to see the signs. This is a guide, not a diagnosis.
Egg-bearing with marine larval phase ·
Females often carry eggs in captivity, but the larvae go through a complex life cycle and are extremely hard to raise, so it is unlikely to breed in a home paludarium.
Not practical.
Brackish paludarium.
Gravid female released.
Hundreds of eggs.
Planktonic larvae.
A small, red-clawed, semi-aquatic crab of estuarine mangroves, kept in brackish paludariums; it must be able to climb out of the water.
Dutch zoologist Wilhem de Haan described this crab in 1835 in Fauna Japonica, a landmark work on Japan's animals. Imported in large numbers from Asia, it is a popular brackish-water crab with bright red claws.
First described by Wilhem de Haan in 1835.
13 facts checked with sources
Invertebrate: semi-terrestrial brackish mangrove crab (sesarmid). Perisesarma bidens is a superseded combination; the accepted name in DecaNet/WoRMS is Parasesarma bidens (De Haan, 1835). Shops still sell it as Perisesarma bidens.
WoRMS / DecaNet record: Perisesarma bidens (accessed 2026-10-16) · WoRMS / DecaNet record: Parasesarma bidens (accessed 2026-10-16) · Fishkeeper (Maidenhead Aquatics): Red-clawed Crab, Perisesarma bidensNew value.
WoRMS / DecaNet record: Parasesarma bidens (accessed 2026-10-16)Body (carapace) size. Fishkeeper gives 4.5 cm maximum; Wikipedia says carapace length up to about 5.1 cm (marked citation needed) and leg span up to 10 cm. Legacy 5 cm is within this range.
Fishkeeper (Maidenhead Aquatics): Red-clawed Crab, Perisesarma bidens · Wikipedia: Parasesarma bidensLegacy 24-28; hobby source gives 24-27.
Fishkeeper (Maidenhead Aquatics): Red-clawed Crab, Perisesarma bidensBrackish water, specific gravity about 1.005.
Fishkeeper (Maidenhead Aquatics): Red-clawed Crab, Perisesarma bidensNew value (legacy had none). Source gives "dH", taken as general hardness.
Fishkeeper (Maidenhead Aquatics): Red-clawed Crab, Perisesarma bidensNo minimum group stated. Source advises only one male per small tank.
Fishkeeper (Maidenhead Aquatics): Red-clawed Crab, Perisesarma bidensMatches legacy "s".
Fishkeeper (Maidenhead Aquatics): Red-clawed Crab, Perisesarma bidensSemi-terrestrial; an aquarium zone does not fit. Should be shown as needing land.
Fishkeeper (Maidenhead Aquatics): Red-clawed Crab, Perisesarma bidensNew value.
Wikipedia: Parasesarma bidens · Fishkeeper (Maidenhead Aquatics): Red-clawed Crab, Perisesarma bidensLegacy says larvae need brackish-marine water; the fetched source confirms a hard larval stage but does not state the salinity needed.
Fishkeeper (Maidenhead Aquatics): Red-clawed Crab, Perisesarma bidensLegacy "high humidity" is not stated by the source.
Fishkeeper (Maidenhead Aquatics): Red-clawed Crab, Perisesarma bidens