Purple arm vampire crab

Care at a glance

Overview

The purple arm vampire crab is a small, semi-terrestrial crab for a humid paludarium. It is a good choice once you have a little experience.

Caring for the purple arm vampire crab

Purple arm vampire crabs are semi-terrestrial, so they need a paludarium rather than an aquarium. Give a colony at least 10 gal (38 L), with 70 to 80 percent land around a shallow freshwater pool. Add fine damp sand, moss, bark and leaf litter to hide in. A tight lid keeps the humidity at 75 to 90 percent.

Keep the water at 75 to 82°F (24 to 28°C), on the alkaline side at a pH of 7.0 to 8.0, and never add copper. Feed sinking pellets, dried leaves, fruit and blanched vegetables. Add protein such as frozen bloodworm, small insects or bits of fish, and offer cuttlebone for molting.

Keep a colony with more females than males. They are mostly peaceful toward their own kind when there are enough hides. They take shrimp, snails and small fish and fight other crabs, so choose any tank mates with caution.

Purple arm vampire crabs develop directly, with the female releasing fully formed young into fresh water. Breeding them is moderately difficult.

Good to know

Geosesarma noduliferum was described by De Man in 1892 from the Tjiparidi River near Buitenzorg, today's Bogor. Males have a violet to blue body, purple claws and pale yellow or white eyes. Its identity was pinned down in 2015 by Ng, Schubart and Lukhaup, who described G. dennerle and G. hagen in the same paper. Shops often sell it as Geosesarma bogorensis, a trade invention that just turns the town name Bogor into Latin. That name is not a described species, though it is recorded as a nomen nudum credited to Whitaker, Roberts, Spicer and Turner 2026.

In the wild

Purple arm vampire crabs come from West Java around Bogor. They live on the forest floor beside streams, and they turn up in rice fields, tea gardens and parks near villages.

Common questions

Related species

• 

  White mandarin vampire crab

  Geosesarma pontianak

  0.6 in (1.5 cm) · 10 gal (38 L)

  0.6 in (1.5 cm)10 gal (38 L)72–82°F (22–28°C)

• 

  Mandarin vampire crab

  Geosesarma notophorum

  0.6 in (1.5 cm) · 16 gal (60 L)

  0.6 in (1.5 cm)16 gal (60 L)72–81°F (22–27°C)

• 

  Purple vampire crab

  Geosesarma dennerle

  1 in (2.5 cm) · 10 gal (38 L)

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

• 

  Blue-leg vampire crab

  Geosesarma bicolor

  2 in (5 cm) · 10 gal (38 L)

  2 in (5 cm)10 gal (38 L)75–82°F (24–28°C)

• 

  Orange vampire crab

  Geosesarma tiomanicum

  2 in (5 cm) · 11 gal (40 L)

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

• 

  Red vampire crab

  Geosesarma hagen

  2 in (5 cm) · 10 gal (38 L)

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