---
title: Shaun the Sheep Slug (Costasiella kuroshimae)
scientific_name: Costasiella kuroshimae
common_name: Shaun the Sheep Slug
taxon: Sap-sucking slugs
published: 2026-08-07T16:29:44.193Z
updated: 2026-08-08T21:49:54.698Z
tags: Shaun the Sheep Slug, Costasiella kuroshimae, Sap-sucking slugs, Red Sea, Marine Life, Diving
url: https://redseacreatures.com/taxon/invertebrate/molluscs/sap-sucking-slugs/shaun-the-sheep-slug
---

# Shaun the Sheep Slug (*Costasiella kuroshimae*)

## Quick facts

- **Group:** Sap-sucking slugs (*Sacoglossa*)
- **Size:** up to 1 cm
- **Depth:** 1-15 m
- **Diet:** Herbivore
- **Activity:** Diurnal
- **Rarity:** Rare
- **Habitat:** On Avrainvillea and other soft green algae
- **Reproduction:** Egg layer, Simultaneous hermaphrodite

## How to recognise it

- under 1 cm, black eyespots and two ringed rhinophores like ears
- back covered in green cerata with white tips
- sits on soft green algal mats
- needs a macro lens to see properly

A slug under 1 cm (0.4 in) that has become an internet celebrity: two ringed rhinophores stand up like ears, two black eyespots sit below them, and the back is covered in green cerata tipped with white, so the whole animal reads as a cartoon sheep grazing a lawn. The resemblance is accidental and complete.

The lawn is real enough - it lives on soft green algae, especially Avrainvillea, puncturing cells and keeping the chloroplasts alive in its cerata, which is why the cerata are green while the body is pale. At this size it is invisible without a macro lens, and finding one is a matter of scanning algal mats centimetre by centimetre rather than swimming a reef. Photographers who know the habit come back with the shot; everyone else swims past several every dive without registering that the fuzz on the weed contains animals.

## Also known as

- **English:** Diamond-mask Sap-sucker, Little Leaf Sheep, Salty Ocean Caterpillar
- **French:** Mouton des mers
- **Japanese:** テングモウミウシ
- **Chinese:** 黑島天兔海蛞蝓
- **Russian:** Костасиелла Курошима

## Range

Mozambique

---

*Source: [Red Sea Creatures](https://redseacreatures.com/taxon/invertebrate/molluscs/sap-sucking-slugs/shaun-the-sheep-slug)*
*Updated: August 8, 2026*