Blue-leg vampire crab

Care at a glance

Overview

Keep them in a colony, ideally one male to two females, in a planted paludarium of about 38 liters with plenty of land and hiding spots. They are aggressive, peaceful enough toward their own kind but hard on other crab species, and they are opportunistic scavengers and hunters that will catch and eat dwarf shrimp, snails, and small fish, so choose tankmates with that in mind. Keep the water warm at 24 to 28 C and alkaline at pH 7.5 to 8, with high ambient humidity. Feed a mixed diet of sinking pellets, dried leaves, blanched veg, and the odd protein treat like bloodworm. Never release unwanted crabs into local waterways, and check your local rules before keeping non-native species.

In the wild

Blue-leg vampire crabs come from forested streams and ponds on Java, Indonesia, where they spend most of their time out of the water on damp banks and leaf litter. They are semi-terrestrial, so do not keep them in a normal tank. Set up a paludarium of about 38 liters with roughly 80 percent land to 20 percent water, 50/50 at the very least, and only 10 to 15 cm of shallow water with an easy exit, since they will drown if kept fully submerged. Plant both the land and water heavily, give them fine sand to burrow in, and keep a tight lid with humidity around 75 percent. Water should run warm, 24 to 28 C, and on the hard alkaline side at pH 7.5 to 8.

Good to know

This is a crab in the family Sesarmidae, reaching about 5 cm across the legs, with a carapace only around 1.5 to 2.5 cm wide. Unlike most crabs it breeds in plain freshwater with no saltwater larval stage, releasing tiny fully formed young, so no brackish water is needed. Geosesarma names are muddled in the trade, and stock sold as G. bicolor is often confused with relatives like G. dennerle, but their care is the same.

Did you know

Most crabs send their young out to sea as drifting larvae, but this one skips that step entirely and hatches miniature crabs straight into freshwater. That is why a colony can slowly build up in a home paludarium without any marine setup, something almost no other crab in the hobby manages.

Related species

• 

  Red vampire crab

  Geosesarma hagen

  2 in (5 cm)10 gal (38 L)72–82°F (22–28°C)
• Orange vampire crab

  Geosesarma tiomanicum

  2 in (5 cm)11 gal (40 L)72–82°F (22–28°C)

• 

  Purple vampire crab

  Geosesarma dennerle

  1 in (2.5 cm)10 gal (38 L)75–82°F (24–28°C)
• Pom Pom Crab

  Ptychognathus barbatus

  1.6 in (4 cm)5 gal (20 L)72–82°F (22–28°C)

• 

  Thai Micro Crab

  Limnopilos naiyanetri

  1 in (2.5 cm)5 gal (20 L)72–82°F (22–28°C)
• Tanganyika Crab

  Platythelphusa sp.

  3.9 in (10 cm)16 gal (60 L)75–82°F (24–28°C)