Polka Dot Hermit Crab care guide
Polka Dot Hermit Crab (Calcinus tibicen) — minimum tank 40 L, temperature 24-26 °C, pH 8.1-8.4.
Compiled by Aquairi from published sources · Published · Updated
Overview
Polka Dot Hermit Crab (Calcinus tibicen) is a marine hermit crab of the family Diogenidae, listed in the Aquairi knowledge base as a beginner-level species. Caribbean hermit with red body covered in distinct white spots. Excellent reef cleanup crew member.
Taxonomy
- Family: Diogenidae
- Genus: Calcinus
- Scientific name: Calcinus tibicen
- Common synonyms: Polka Dot Hermit, Caribbean Polkadot Hermit
Habitat
Hermit crabs of the family Diogenidae are anomuran crustaceans that protect their soft, asymmetric abdomen inside an empty gastropod shell, moving to larger shells as they grow. Reef species graze algae, biofilm and detritus across the rockwork and substrate. In the Aquairi knowledge base this species is recorded from Caribbean.
Tank requirements
- Minimum tank volume: 40 L (10.6 US gal)
- Adult size: 2-3 cm
- Temperature: 24-26 °C (75-79 °F)
- pH: 8.1-8.4
- GH: 8-12 °dGH
- KH: 8-12 °dKH
- Salinity (specific gravity): 1.024-1.026
- Lifespan: 2-5 years
Diet
The species is an omnivore, grazing algae, biofilm and detritus across the rockwork and substrate; in aquaria its diet is supplemented with dried algae and sinking foods when natural growth is scarce.
Compatibility
The Aquairi knowledge base lists this species as peaceful. Suitable tank mates include Reef fish, Other hermits. It should be kept away from Snails (provide spare shells).
Breeding
Breeding requires an extended planktonic larval stage in open water before the young settle, which makes captive reproduction very difficult and rarely accomplished in home aquaria. Most specimens in the hobby are wild-collected.
Breeding the Polka Dot Hermit Crab (Calcinus tibicen)
Overview
Calcinus tibicen is a hermit crab widely distributed in the western Atlantic, from the United States and Gulf of Mexico through Bermuda, Florida, the Caribbean, Colombia, Panama and Venezuela to southern Brazil. It is an intertidal-to-shelf species occurring from the lower intertidal down to about 200 m. Semi-gregarious, it occupies empty gastropod shells and works the reef as a cleanup grazer.
Sexing
Sex is determined by gonopores at the leg bases, awkward to view inside an occupied shell. Females become obvious when ovigerous, brooding eggs on the abdomen; the egg count per female is large and varies widely with body size, attributed to multiple or fragmented spawnings across the reproductive cycle.
Spawning & Larvae
The female broods fertilized eggs on her abdomen inside the shell until hatching. As in hermit crabs generally, the nauplius and protozoea stages pass within the egg, and the larvae hatch at the zoea stage; the planktonic zoeae then feed and develop in the water column before a post-larval stage settles and takes a first shell.
Common Challenges
- Planktonic zoeae are captured by skimmers, filters and pump intakes in a closed system.
- Larvae need live planktonic food and steady water parameters a display cannot offer.
- Newly settled crabs depend on a supply of small empty shells.
- Variable, fragmented spawnings make timed larval collection unreliable in captivity.