Calcinus gaimardii is a small and active hermit crab, often used as part of a reef aquarium clean-up crew. The species is known for its brightly colored legs and constant movement over rockwork and sand.

The hermit crab feeds on algae, detritus, and other organic waste, which helps keep the aquarium cleaner. The species needs empty snail shells as it grows, as it will move into a larger shell as its size increases.
Due to its small size, Calcinus gaimardii is also well-suited for nano aquariums. However, like other hermit crabs, it may move loose coral frags or knock over lightly attached corals as it moves around.

Features
Helps control algae and detritus
Active and interesting behavior
Suitable for nano aquariums
Requires empty shells as it grows
May move loose corals
Care Instructions
Minimum aquarium size: 30 l
Temperature: 24–26 °C
Salinity: 1.023–1.026
Feeding: algae, detritus, bottom feeds, frozen foods
Compatibility: peaceful with most fish and invertebrates
Reef safe: largely reef safe
Additional Information
Scientific name: Calcinus gaimardii
English name: Dwarf Hermit Crab
Finnish name: Erakkorapu
Origin: Indo-Pacific
Difficulty level: Easy