TankBud

Blue-leg vampire crab

Geosesarma bicolor

Also known as Vampire crab

FreshwaterCrab

Blue-leg vampire crab (Geosesarma bicolor)

Care at a glance

Temperature
75–82°F
24–28°C
pH
7.5–8.0
Adult size
2 in
5 cm
Minimum tank
10 gal
38 L
Temperament
Mostly peaceful
Social behavior
Social
Tankmates
With caution
Swim level
Bottom
Diet
Omnivore
Difficulty
Medium
Breeding
Hard
Rarity
Common
Family
Sesarmidae
Origin
Java, Indonesia (forested streams/ponds)

Overview

The blue-leg vampire crab is a small, semi-terrestrial crab for a planted paludarium. It is best with a little experience.

Did you know

The blue-leg vampire crab skips the drifting larval stage that most crabs send out to sea. That lets a colony slowly build up in a home paludarium, which almost no other crab in the hobby manages.

Caring for the blue-leg vampire crab

Blue-leg vampire crabs are semi-terrestrial and drown if kept fully submerged, so keep them in a paludarium, not a normal tank. Give a colony at least 10 gal (38 L), with roughly 80 percent land to 20 percent water, or 50/50 at the very least. Keep only 10 to 15 cm of shallow water, with an easy exit.

Plant both the land and the water heavily, and give them fine sand to burrow in and plenty of hiding spots. Fit a tight lid, and keep the humidity around 75 percent. Keep the water warm and on the hard, alkaline side, at 75 to 82°F (24 to 28°C) and a pH of 7.5 to 8.0.

Feed a mixed diet of sinking pellets, dried leaves, blanched vegetables and the odd protein treat such as bloodworm. Blue-leg vampire crabs are opportunistic scavengers and hunters that will catch and eat dwarf shrimp, snails and small fish. Choose tank mates with that in mind.

Keep them as a colony, ideally one male to two females. They are mostly peaceful and get along with their own kind, but they are hard on other crab species.

Their eggs hatch as miniature crabs straight into fresh water, so no brackish water is needed. Breeding them is hard. Never release unwanted crabs into local waterways, and check your local rules before keeping non-native species.

Good to know

The blue-leg vampire crab is a member of the family Sesarmidae. Its size is measured across the legs, and the carapace itself is only around 1.5 to 2.5 cm wide. Geosesarma names are muddled in the trade, and stock sold as G. bicolor is often confused with relatives like G. dennerle. Their care is the same.

In the wild

Blue-leg vampire crabs come from forested streams and ponds on Java, Indonesia. They spend most of their time out of the water, on damp banks and in leaf litter.

Common questions

What size tank does a blue-leg vampire crab need?

A blue-leg vampire crab needs at least 10 gal (38 L). It spends most of its time in the bottom.

What temperature and pH does a blue-leg vampire crab need?

A blue-leg vampire crab is comfortable at 75–82°F (24–28°C) with a pH of 7.5–8.0.

What does a blue-leg vampire crab eat?

A blue-leg vampire crab eats a mixed diet of sinking pellets, dried leaves, blanched vegetables and the odd protein treat such as bloodworm. It also catches and eats dwarf shrimp, snails and small fish.

How big does a blue-leg vampire crab get?

An adult blue-leg vampire crab reaches about 2 in (5 cm).

How does a blue-leg vampire crab breed?

A blue-leg vampire crab's eggs hatch as miniature crabs straight into fresh water, so it needs no brackish water to breed. Breeding it is hard.

Related species