Breeding the Zebra Hermit Crab (Calcinus laevimanus)

Calcinus laevimanus is an Indo-Pacific hermit crab that carries eggs year-round; the larvae pass through six zoeal stages and a glaucothoe in the plankton, so it is not bred in home reef tanks.

Overview

Calcinus laevimanus (Randall, 1840) is a hermit crab of the tropical western Indo-Pacific from East Africa to Hawaii, living between the low intertidal and upper subtidal on rocky reefs and rubble. Total length reaches about 30 mm; the left claw is conspicuously larger than the right. It occupies globose gastropod shells, favouring Turbo and Nerita shells, and serves as a reef cleanup grazer.

Sexing

Sex is read from the gonopores on the leg bases, hard to inspect within an occupied shell; males also tend to be larger than females. Ovigerous females are visible when eggs are carried on the abdomen inside the shell, and in Hawaii roughly 80% of females carry eggs between February and October.

Spawning & Larvae

Females carry eggs year-round in this species, brooding the clutch on the abdomen until hatching. The larvae are planktonic and progress through six zoeal stages followed by a single glaucothoe (post-larval) stage in the water column before settling and adopting a first shell as a juvenile crab.

Common Challenges

• Six zoeal stages plus a glaucothoe make a long planktonic cycle that closed tanks cannot sustain.
• Tiny zoeae are removed by skimmers, filters and pumps and require live plankton food.
• Settled juveniles need a steady supply of small empty shells to occupy.
• Maintaining stable temperature and salinity through the whole larval period is impractical at home.