---
title: Tubed Siphonfish (Siphamia tubifer)
scientific_name: Siphamia tubifer
common_name: Tubed Siphonfish
taxon: Cardinals
conservation_status: LC - Least Concern
published: 2024-11-08T21:50:45.086Z
updated: 2026-08-15T13:15:27.691Z
tags: Tubed Siphonfish, Siphamia tubifer, Cardinals, Red Sea, Marine Life, Diving
url: https://redseacreatures.com/taxon/fishes/bony-fishes/cardinals/tubed-siphonfish
---

# Tubed Siphonfish (*Siphamia tubifer*)

## Quick facts

- **Group:** Cardinals (*Apogonidae*)
- **Size:** up to 7 cm
- **Depth:** 1-100 m
- **Diet:** Carnivore
- **Activity:** Nocturnal
- **Rarity:** Uncommon
- **Habitat:** Among the spines of long-spined sea urchins
- **Reproduction:** Mouthbrooder, Gonochoric
- **Conservation status:** LC - Least Concern

## How to recognise it

- small translucent silvery fish with a dark stripe from eye to tail
- always among the spines of a Diadema urchin, head down
- belly with a pale strip along the gut - the light organ
- length up to 7 cm

A small silvery fish hanging head-down between the spines of a sea urchin, and one of the very few animals here that carries its own light.

The organ runs along the gut and is packed with luminous bacteria the fish acquires from seawater as a juvenile - not inherited, acquired, and only one bacterial species out of everything in the water will do. It feeds them and houses them; they glow. The light shines downward through the muscle, and the working theory is counter-illumination: from below the fish is lit to match the surface glow, so its silhouette disappears.

The urchin is the other half of the arrangement. These fish spend their entire lives among the spines of *Diadema*, turning to keep the spines between themselves and anything approaching, and a group of them will rotate around the urchin as a diver circles it.

Males brood the eggs in the mouth and do not feed while they carry them - the family's rule. Seven centimeters (3 in), and easily overlooked as a reflection between the spines.

## Also known as

- **English:** Tubifer Cardinalfish, Sea Urchin Cardinalfish, Two-spot Urchin Cardinalfish
- **French:** Apogon des oursins
- **Portuguese:** Cardeal-de-ouriço-do-mar
- **Czech:** parmovec ježovkový, parmovec měňavý
- **Japanese:** ヒカリイシモチ, Hikariishimochi
- **Chinese:** 大目側仔, 大面側仔, 變色管天竺鯛

## Scientific synonyms

- *Beanea trivittata* Steindachner, 1902
- *Siphamia cuprea* Lachner, 1953
- *Siphamia ovalis* Lachner, 1953
- *Siphamia permutata* Klausewitz, 1966

---

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