---
title: Boxer Crab (Lybia caestifera)
scientific_name: Lybia caestifera
common_name: Boxer Crab
taxon: Crabs
published: 2026-08-08T21:11:47.661Z
updated: 2026-08-09T05:49:42.113Z
tags: Boxer Crab, Lybia caestifera, Crabs, Red Sea, Marine Life, Diving
url: https://redseacreatures.com/taxon/invertebrate/crustaceans/crabs/boxer-crab
---

# Boxer Crab (*Lybia caestifera*)

## Quick facts

- **Group:** Crabs (*Brachyura*)
- **Size:** up to 1.5 cm
- **Depth:** 1-25 m
- **Diet:** Detritivore
- **Activity:** Nocturnal
- **Rarity:** Uncommon
- **Habitat:** Under stones and coral rubble in the shallows
- **Reproduction:** Brooder, Gonochoric

## How to recognise it

- a small anemone gripped in each claw, held out in front
- pale shell with a fine dark mosaic pattern
- walks with the claws raised, never using them to pinch
- width up to 1.5 cm

A crab barely 1.5 cm (0.6 in) across, its pale shell patterned in a fine dark mosaic, and a small anemone held in each claw like a pair of gloves. The claws are too small to fight with and are never used for it: they exist to carry the weapon, and the crab waves the anemones at anything that comes close.

The anemone is usually Triactis producta, and the arrangement is one-sided. The crab wipes its anemones across the substrate and eats what sticks to them, so the anemone loses part of every meal and stays small. Deprived of one, a crab will tear the remaining anemone in half and wait for both pieces to regrow - which is where the aquarium trade's supply comes from. Females carry eggs under the abdomen and continue to hold the anemones throughout. Look under stones in shallow rubble at night; the crab itself is almost invisible, but the two pale dots it holds up are not.

## Also known as

- **Japanese:** ヒメキンチャクガニ
- **Russian:** Краб-боксёр

## Scientific synonyms

- *Melia caestifer* Alcock, 1898

## Range

South Pacific Ocean

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