TankBud

Batik crab

Metasesarma obesum

Also known as Marble crab, Marble batik crab, Mottled crab, Batik vampire crab, Emerald land crab

FreshwaterBrackishCrab

Care at a glance

Temperature
72–82°F
22–28°C
pH
7.0–8.0
Adult size
1 in
2.5 cm
Minimum tank
11 gal
40 L
Temperament
Mostly peaceful
Social behavior
Social
Tankmates
With caution
Swim level
Bottom
Diet
Omnivore
Difficulty
Medium
Breeding
Egg carrier
Rarity
Rare
Family
Sesarmidae
Origin
Indo-Pacific beaches, Indonesia to East Africa

Overview

The batik crab is a small, sociable crab for a humid terrarium with shallow water dishes. It suits a keeper with a little experience.

Did you know

The batik crab is a shore animal, unlike the vampire crabs. It is sold as a freshwater crab, but its home is the brackish and salt edge of the beach.

Caring for the batik crab

The batik crab is a land crab that drowns in deep water, so keep it in a humid terrarium, not an aquarium. Give it at least 11 gal (40 L), with about 90 percent land of damp sand and coco fiber, bark and leaf litter. Add a shallow dish of fresh water that it can climb out of easily, and fit a tight lid.

Keep the air at 72 to 82°F (22 to 28°C) and 70 to 90 percent humidity. Hold the freshwater dish at a pH of 7.0 to 8.0, and never use copper. The crab does fine with only fresh water, but many keepers add a second dish of brackish to salt water. Set it at a specific gravity of 1.005 to 1.015, and the crabs will use both.

Batik crabs lean carnivorous. Feed bits of fish, worms, crickets, shrimp and crab pellets, with fruit and vegetables a few times a week. Add cuttlebone for calcium.

Batik crabs are sociable, and a group of three to five can live together if the terrarium has enough space and hides. They are mostly peaceful toward each other, but males grapple over territory when crowded. They hunt and eat white isopods and springtails, so choose any tank mates with caution.

Females carry hundreds of tiny eggs. The eggs hatch into planktonic larvae that need the sea, so the female walks down the beach to release them into the surf. No one has yet reared those larvae to crabs in captivity.

Good to know

Metasesarma obesum is a sesarmid crab, described by Dana in 1851. It is the sister species of the red apple crab, Metasesarma aubryi. Its legspan reaches 4 to 5 cm. The marbled brown, cream and green pattern varies from crab to crab, which gave it the trade names batik crab and marble crab. Every batik crab in the trade is wild caught. A batik crab can be expected to live 2 to 3 years.

In the wild

Batik crabs live on tropical beaches around the Indian and western Pacific Oceans, from Indonesia and the Philippines to Madagascar and Zanzibar. They stay above the tide line, where the sand meets the forest, and hide under stones, driftwood, leaf litter and coral rubble.

Common questions

What size tank does a batik crab need?

A batik crab needs at least 11 gal (40 L). It spends most of its time in the bottom.

What temperature and pH does a batik crab need?

A batik crab is comfortable at 72–82°F (22–28°C) with a pH of 7.0–8.0.

What does a batik crab eat?

A batik crab leans carnivorous, taking bits of fish, worms, crickets, shrimp and crab pellets. Give it fruit and vegetables a few times a week, plus cuttlebone for calcium.

How big does a batik crab get?

An adult batik crab reaches about 1 in (2.5 cm).

How does a batik crab breed?

A female batik crab carries hundreds of tiny eggs, then releases the planktonic larvae into the surf. No one has yet reared those larvae to crabs in captivity.

Related species