Not furry either, still lovely.

Red Claw Crab

Perisesarma bidens

Also called Red-clawed crab, Parasesarma bidens (alternative name)

SpeciesShort profile

From Indo-Pacific, from Zanzibar to Japan and Fiji; lives in mangroves1 2

At a glance the quick version

Lengthup to 5.1 cm1

Sizesmall

Bright red claws

Climbs as well as walks, using both ground and branches

At home in brackish water

1 2

Looks how to spot one

Small semi-terrestrial mangrove crab

A small crab with a carapace usually no more than about 5 cm across and a leg span reaching around 10 cm. It is named for its eye-catching red claws.1

Coloursred claws1

Daily activity how busy a day looks

Moves between the ground and mangrove trees, living both on the bottom and among branches.2

Grooming and care the hands-on bits

A brackish-water species from warm mangrove areas; an enclosure should combine water and dry areas to climb on.2

Home where they are happiest

Brackish mangrove areas in subtropical and tropical coasts, where it uses both the muddy floor and the trees.2

The story where it all began

De Haan described the species in 1835 as Grapsus bidens, and it has been moved between several genera since. It belongs to the Sesarmidae, a family of crabs that includes several truly land-living genera.1 3

Fun facts for the dinner table

1
Its leg span can be about twice the width of its shell.1
2
In mangroves it lives both on the ground and up in the trees.2
3
Its natural range stretches from East Africa's Zanzibar all the way to Japan and Fiji.1

Recognised by the official bits

Willem de Haan: Described in 1835 as Grapsus bidens1

The care rhythm Furry Diary remembers it for you

A typical home-care rhythm for a Red Claw Crab. It is our own starting plan, not a vet's advice, and you can change every line in the app.

FeedingSmall amounts once or twice a dayevery day
Temperature checkevery day
Salinity checkBrackish fish need a little marine salt, and some need more as they growevery week
Water changeAbout 25% of the water, mixed to the same salinityevery week
Water testevery week
Filter rinseRinse in old tank water, never tap waterevery month

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Where this comes from

Every breed page shows where each fact comes from. If we got something wrong, sorry, we are pet people, not a science magazine. Tell us at support@furrydiary.app and we will fix it.

Wikipedia: Perisesarma bidens en.wikipedia.orgused for common name, range, size, naming history
SeaLifeBase: Parasesarma bidens sealifebase.seused for environment, mangrove habitat, ground and tree living
Wikipedia: Sesarmidae en.wikipedia.orgused for family background

Checked 2026-09-30. Text is written in our own words from these sources.