---
title: Blackbordered Dascyllus (Dascyllus marginatus)
scientific_name: Dascyllus marginatus
common_name: Blackbordered Dascyllus
taxon: Pomacentridae
conservation_status: LC - Least Concern
published: 2024-11-14T17:25:24.897Z
updated: 2026-08-15T14:13:53.280Z
tags: Blackbordered Dascyllus, Dascyllus marginatus, Pomacentridae, Red Sea, Marine Life, Diving
url: https://redseacreatures.com/taxon/fishes/bony-fishes/pomacentridae/blackbordered-dascyllus
---

# Blackbordered Dascyllus (*Dascyllus marginatus*)

## Quick facts

- **Group:** Pomacentridae (*Pomacentridae*)
- **Size:** up to 6 cm
- **Depth:** 1-15 m
- **Diet:** Omnivore
- **Activity:** Diurnal
- **Rarity:** Common
- **Habitat:** Branching Porites and Acropora heads in shallow water
- **Reproduction:** Egg layer, Protogynous hermaphrodite
- **Endemic:** Endemic to the Red Sea
- **Conservation status:** LC - Least Concern

## How to recognise it

- pale yellow-brown body with a black margin along the dorsal fin
- small - the smallest damselfish of its genus here
- in tight groups inside a single coral head
- length up to 6 cm

A small pale damselfish with a black-edged dorsal fin, in a tight group inside a branching coral head, and one that lives in this sea and the Gulf of Aden and nowhere else.

Six centimeters (2.4 in) makes it the smallest of its genus here, and the size fits the habit: it lives deeper inside the branches than its striped relatives, and it rarely leaves the colony at all. A group of them in a Porites head is effectively a population living in a single organism.

That dependence is total. These fish do not relocate as adults, so a colony that dies takes its residents with it - and the coral benefits in turn from the nutrients they release and the water they keep moving through the branches. Both sides lose when one goes.

Like its relatives it lives in a size-ordered group with one breeding pair, and males guard eggs laid on a cleaned patch at the base of the coral.

## Also known as

- **English:** blackbordered dascyllus, Grey Humbug, Red Sea Dascyllus
- **Hebrew:** אלמוגית שוליים
- **French:** Demoiselle de mer Rouge
- **Italian:** Damigella del Mar Rosso, Damigella bordata
- **Spanish:** Damisela del Mar Rojo
- **Portuguese:** Dascyllus-do-Mar-Vermelho, Dascyllus-papagaio
- **Dutch:** Rode Zee-juffertje
- **Czech:** komorník arabský
- **Russian:** Серый дасцилл
- **CA:** Dascyllus del Mar Roja
- **TH:** ปลาสลิดหินหน้าสั้น

## Scientific synonyms

- *Dascyllus marginatus marginatus* (Rüppell, 1829)
- *Pomacentrus marginatus* Rüppell, 1829

## Range

Mozambique, Red Sea

---

*Source: [Red Sea Creatures](https://redseacreatures.com/taxon/fishes/bony-fishes/pomacentridae/blackbordered-dascyllus)*
*Updated: August 15, 2026*