---
title: Decorated Thuridilla (Thuridilla decorata)
scientific_name: Thuridilla decorata
common_name: Decorated Thuridilla
taxon: Sap-sucking slugs
published: 2026-08-07T16:29:44.182Z
updated: 2026-08-20T17:09:46.265Z
tags: Decorated Thuridilla, Thuridilla decorata, Sap-sucking slugs, Red Sea, Marine Life, Diving
url: https://redseacreatures.com/taxon/invertebrate/molluscs/sap-sucking-slugs/decorated-thuridilla
---

# Decorated Thuridilla (*Thuridilla decorata*)

## Quick facts

- **Group:** Sap-sucking slugs (*Sacoglossa*)
- **Size:** up to 3 cm
- **Depth:** 1-20 m
- **Diet:** Herbivore
- **Activity:** Diurnal
- **Rarity:** Uncommon
- **Habitat:** Algal turf on shallow reef rock
- **Reproduction:** Egg layer, Simultaneous hermaphrodite

## How to recognise it

- dark body with bright orange and blue-white lines along the flaps
- flaps held upright and close together, not spread flat
- small, up to 3 cm
- crawls openly over algal turf in daylight

A small, boldly marked sacoglossan to about 3 cm (1.2 in): a dark body ruled with bright orange and blue-white lines, the flaps carried upright and close together rather than spread flat as in Elysia. It crawls openly over algal turf in daylight, and at that size the color is what catches the eye.

Bright markings on an animal that makes no attempt to hide usually mean it is not worth eating, and that holds here - sacoglossans carry compounds taken from the algae they drain. Feeding is the group's standard method: a one-toothed radula punctures a cell, the contents are sucked out, and the chloroplasts are kept alive inside the slug. Almost all records of this species come from this sea and its immediate surrounds, which makes it a local speciality among a group otherwise spread across the Indo-Pacific.

## Also known as

- **Russian:** Туридилла украшенная

## Scientific synonyms

- *Elysia decorata* Heller & T. E. Thompson, 1983

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*Source: [Red Sea Creatures](https://redseacreatures.com/taxon/invertebrate/molluscs/sap-sucking-slugs/decorated-thuridilla)*
*Updated: August 20, 2026*