---
title: Goldbelly Cardinalfish (Ostorhinchus apogonoides)
scientific_name: Ostorhinchus apogonoides
common_name: Goldbelly Cardinalfish
taxon: Cardinals
conservation_status: LC - Least Concern
published: 2024-11-08T20:02:24.427Z
updated: 2026-08-18T21:13:35.410Z
tags: Goldbelly Cardinalfish, Ostorhinchus apogonoides, Cardinals, Red Sea, Marine Life, Diving
url: https://redseacreatures.com/taxon/fishes/bony-fishes/cardinals/goldbelly-cardinalfish
---

# Goldbelly Cardinalfish (*Ostorhinchus apogonoides*)

## Quick facts

- **Group:** Cardinals (*Apogonidae*)
- **Size:** up to 10 cm
- **Depth:** 3-60 m
- **Diet:** Planktivore
- **Activity:** Nocturnal
- **Rarity:** Common
- **Habitat:** Reef slopes and drop-offs
- **Reproduction:** Mouthbrooder
- **Conservation status:** LC - Least Concern

## How to recognise it

- translucent body with a bright silver-gold belly
- fine dark line along the flank
- large eye, dark bar through it
- up to 10 cm

The belly is a mirror, and that is the point.

A fish hanging in midwater is lit from above, which means its underside is in shadow and shows as a dark shape to anything looking up at it from below. Countershading fixes that by making the belly pale, and the extreme version of pale is silver: a mirrored surface reflects the water around it and effectively cancels the animal's outline from underneath. Herring do it, sardines do it, and so does this cardinalfish, whose belly carries a bright silver-gold sheen against an otherwise translucent body.

It matters most at exactly the hours this fish works. At dusk and through the night, when the surface still carries some light and the water below is black, a predator hunting from beneath is looking at a bright ceiling with silhouettes on it. A mirrored belly is the difference between being one of those silhouettes and not.

By day it holds under ledges and along drop-offs in loose groups, at night it spreads into the water column for zooplankton, and the male broods the eggs in his mouth.

## Also known as

- **English:** Short-tooth Cardinal, Diamond Cardinal, Goldbelly Cardinalfish
- **French:** Apogon au ventre doré, Apogon à ventre doré, Cardinal Masqué
- **Portuguese:** Cardeal-australiano
- **Czech:** parmovec zlatobřichý
- **Japanese:** アオハナテンジクダイ, Aohanatenjikudai
- **Chinese:** 大目側仔, 大面側仔, 短牙鸚竺鯛
- **Russian:** Мелкозубый апогон
- **TAH:** 'upaparu

## Scientific synonyms

- *Apogon apogonides* (Bleeker, 1856)
- *Apogon apogonoides* (Bleeker, 1856)
- *Apogon enigmaticus* (Smith, 1961)
- *Apogonichthyoides enigmaticus* Smith, 1961
- *Cheilodipterus apogonides* Bleeker, 1856
- *Cheilodipterus apogonoides* Bleeker, 1856
- *Cheilodipterus apogonoïdes* Bleeker, 1856
- *Ostorhinchus apogonides* (Bleeker, 1856)
- *Ostorhynchus apogonides* (Bleeker, 1856)

---

*Source: [Red Sea Creatures](https://redseacreatures.com/taxon/fishes/bony-fishes/cardinals/goldbelly-cardinalfish)*
*Updated: August 18, 2026*