---
title: Headshield Slug (Chelidonura livida)
scientific_name: Chelidonura livida
common_name: Headshield Slug
taxon: Opisthobranchia
published: 2024-04-15T09:05:04.422Z
updated: 2026-08-15T20:04:39.728Z
tags: Headshield Slug, Chelidonura livida, Opisthobranchia, Red Sea, Marine Life, Diving
url: https://redseacreatures.com/taxon/invertebrate/molluscs/opisthobranchia/headshield-slug
---

# Headshield Slug (*Chelidonura livida*)

## Quick facts

- **Group:** Opisthobranchia (*Opisthobranchia*)
- **Size:** up to 5 cm
- **Depth:** 0-15 m
- **Diet:** Carnivore
- **Activity:** Diurnal
- **Rarity:** Common
- **Habitat:** Sand and rubble flats, shallow lagoons
- **Reproduction:** Egg layer, Simultaneous hermaphrodite

## How to recognise it

- black body with fine blue-white lines and orange margins
- flattened shield over the head, with no visible tentacles
- two unequal tail lobes trailing behind
- length up to 5 cm

A black slug lined in blue-white and edged in orange, gliding over sand with a flat shield over its head and two unequal tails trailing behind.

The shield is the tool the group is named for. It is a smooth wedge used to plow through the top layer of sand without the animal having to lift anything, so the slug can hunt below the surface while moving. There are no tentacles on top - they would be in the way.

What it hunts is worth knowing: flatworms, and small ones almost exclusively. Headshield slugs follow the mucus trail a flatworm leaves, catch up with it, and swallow it whole - one of the few predators of a group that is otherwise very well defended chemically.

It is a simultaneous hermaphrodite like other sea slugs, and it lays a coiled ribbon of eggs in the sand. Five centimeters (2 in), common on shallow sand flats, and usually found by noticing a moving line of blue where nothing should be moving.

## Also known as

- **English:** Blue-ringed Swallowtail, Blue-spotted Shield Slug
- **Hebrew:** דו-זנבית סגולה
- **French:** Chélinodure bleue
- **Japanese:** アオテンツバメガイ

## Range

India, Israeli part of the Gulf of Aqaba, Mozambique, South Africa

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*Source: [Red Sea Creatures](https://redseacreatures.com/taxon/invertebrate/molluscs/opisthobranchia/headshield-slug)*
*Updated: August 15, 2026*