---
title: Red Reef Crab (Liomera rubra)
scientific_name: Liomera rubra
common_name: Red Reef Crab
taxon: Crabs
published: 2026-08-08T21:11:47.691Z
updated: 2026-08-09T05:28:40.287Z
tags: Red Reef Crab, Liomera rubra, Crabs, Red Sea, Marine Life, Diving
url: https://redseacreatures.com/taxon/invertebrate/crustaceans/crabs/red-reef-crab
---

# Red Reef Crab (*Liomera rubra*)

## Quick facts

- **Group:** Crabs (*Brachyura*)
- **Size:** up to 2 cm
- **Depth:** 1-25 m
- **Diet:** Detritivore
- **Activity:** Nocturnal
- **Rarity:** Uncommon
- **Habitat:** Under coral slabs and in rubble
- **Reproduction:** Brooder, Gonochoric
- **Hazard:** Poisonous

## How to recognise it

- smooth glossy shell in plain deep red
- shell wider than long, edges finely scalloped
- short stout claws with dark tips
- width up to 2 cm

A small crab with a smooth glossy shell in plain deep red, wider than it is long and finely scalloped along the front edges. About 2 cm (0.8 in) across, with short stout claws tipped dark.

The colour is the point. Bright uniform red on a small, slow, defenceless crab is the classic signature of a chemically defended animal, and several crabs in this family are known to carry paralytic toxins in their flesh - the same compounds found in pufferfish and in some cone snails. Predators learn the pattern; a diver only needs to know not to eat it. It shelters under coral slabs and in rubble by day, feeding at night on detritus and algal film, and turns up on night dives as a spot of red under a torch when everything else has gone grey.

## Also known as

- **English:** red liomera
- **Japanese:** シロスジベニオウギガニ
- **Russian:** Лиомера красная

## Scientific synonyms

- *Carpilodes coccineus* Rathbun, 1906
- *Carpilodes ruber* A. Milne-Edwards, 1865

## Range

Madagascar, Mascarene Islands, Mozambique Channel, Republic of Mauritius, South Pacific Ocean, Tanzania

---

*Source: [Red Sea Creatures](https://redseacreatures.com/taxon/invertebrate/crustaceans/crabs/red-reef-crab)*
*Updated: August 9, 2026*