---
title: Hermit Crab Anemone (Calliactis polypus)
scientific_name: Calliactis polypus
common_name: Hermit Crab Anemone
taxon: Sea anemones
published: 2026-08-09T06:00:11.400Z
updated: 2026-08-09T06:48:40.058Z
tags: Hermit Crab Anemone, Calliactis polypus, Sea anemones, Red Sea, Marine Life, Diving
url: https://redseacreatures.com/taxon/invertebrate/stinging/sea-anemones/hermit-crab-anemone
---

# Hermit Crab Anemone (*Calliactis polypus*)

## Quick facts

- **Group:** Sea anemones (*Actiniaria*)
- **Size:** up to 4 cm tall
- **Depth:** 1-40 m
- **Diet:** Carnivore
- **Activity:** Cathemeral
- **Rarity:** Uncommon
- **Habitat:** On shells occupied by hermit crabs
- **Reproduction:** Broadcast spawner, Gonochoric
- **Hazard:** Venomous

## How to recognise it

- small anemone sitting on a hermit crab's shell, several at a time
- brownish column streaked paler, short tentacles
- releases white stinging threads when disturbed
- height up to 4 cm

A small brownish anemone with a streaked column and short tentacles, found not on rock but on the shell a hermit crab is carrying - often three or four to a shell, arranged where they get the best of the current.

The partnership is deliberate on both sides. The crab picks anemones up and presses them onto its shell, working at the base until the animal releases its grip and transfers; when the crab outgrows the shell and moves, it takes the anemones with it. The anemone gains transport and the scraps of the crab's meals, the crab gains a stinging cover that deters octopus. Disturbed, the anemone fires white threads loaded with stinging cells, and a diver who lifts the shell will feel them on thin skin. Look on the larger hermit crabs of sand and rubble, especially Dardanus.

## Also known as

- **Russian:** Актиния рака-отшельника

## Scientific synonyms

- *Actinia decorata* Couthouy in Dana, 1846
- *Actinia polypus*
- *Adamsia decorata*
- *Adamsia miriam* Haddon & Shackleton, 1893
- *Calliactis decorata* (Drayton in Dana, 1849)
- *Calliactis miriam* Haddon & Shackleton, 1893
- *Cribrina (Tristemma) polypus* Ehrenberg
- *Priapus polypus* Forsskål, 1775

## Range

Andaman Sea, Cape Verde, Costa Rica, Djibouti, Ecuador, Gulf of California, Gulf of Mexico, Japan, Marshall Islands, Mozambique, Philippines, Red Sea, South Pacific Ocean, Tanzania, United States

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*Source: [Red Sea Creatures](https://redseacreatures.com/taxon/invertebrate/stinging/sea-anemones/hermit-crab-anemone)*
*Updated: August 9, 2026*