---
title: Thornback Cowfish (Lactoria fornasini)
scientific_name: Lactoria fornasini
common_name: Thornback Cowfish
taxon: Boxfishes
published: 2026-08-11T10:12:03.870Z
updated: 2026-08-11T10:22:42.662Z
tags: Thornback Cowfish, Lactoria fornasini, Boxfishes, Red Sea, Marine Life, Diving
url: https://redseacreatures.com/taxon/fishes/bony-fishes/boxfishes/thornback-cowfish
---

# Thornback Cowfish (*Lactoria fornasini*)

## Quick facts

- **Group:** Boxfishes (*Ostraciidae*)
- **Size:** up to 23 cm
- **Depth:** 3-40 m
- **Diet:** Carnivore
- **Activity:** Diurnal
- **Rarity:** Uncommon
- **Habitat:** Sheltered reef, rubble and seagrass
- **Reproduction:** Broadcast spawner, Gonochoric
- **Hazard:** Poisonous

## How to recognise it

- boxy armored body with a pair of horns over the eyes and another pair at the rear
- single backward-pointing spine in the middle of the back
- blue lines and spots over an olive to yellow ground
- sculls with tiny fins, body held rigid

A box with horns. The body is a rigid armored shell of fused plates with a pair of spines above the eyes, another pair at the rear, and - the detail that names it - a single backward-pointing thorn in the middle of the back. Blue lines and spots wander over an olive to yellow ground, and the whole thing moves by sculling with fins so small they look borrowed.

The armor is a trade. Nothing about this fish is fast or flexible, and it does not need to be: a rigid box is hard to bite and awkward to swallow. What it loses in maneuvering it gains in not having to. It hovers over rubble and seagrass, blowing jets of water at the sand to expose worms and small crustaceans.

The second defense is chemical. Boxfishes release ostracitoxin from the skin when badly stressed, potent enough to kill other fish in a confined space - which is why one dying in a bucket or a home tank can take everything else with it. In the sea it is harmless to watch, and slow enough that a photographer gets several attempts.

## Also known as

- **English:** Thornback Cowfish, Backspine Cowfish, Spiny-backed Cow-fish
- **French:** Poisson-vache à épine dorsale
- **Italian:** Pesce scatola cornuto spinoso
- **German:** Dornrücken-Kofferfisch, Rückendorn-Kofferfisch
- **Spanish:** Pez vaca espinoso
- **Portuguese:** Peixe-vaca-de-dorso-espinhoso
- **Czech:** havýš trnohřbetý
- **Japanese:** シマウミスズメ, Shima-umisuzume, Shimaumisuzume
- **Chinese:** 海牛港, 福氏角箱魨, 箱河魨
- **Russian:** Кузовок-рогач шипастый
- **CA:** Vaqueta espinosa
- **DA:** Tornrygget kuffertfisk
- **FIJ:** ucurua
- **KO:** 줄무늬뿔복
- **MSA:** Buntal batu, Buntal kotak, Buntal kumbang

## Scientific synonyms

- *Lactoria fuscomaculata* von Bonde, 1923
- *Lactoria galeodon* Jenkins, 1903
- *Lactoria pentacanthus* (Bleeker, 1857)
- *Ostracion fornasini* Bianconi, 1846
- *Ostracion pentacanthus* Bleeker, 1857

## Range

Kenya, Madagascar, Mozambique, Seychelles, South Africa

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*Source: [Red Sea Creatures](https://redseacreatures.com/taxon/fishes/bony-fishes/boxfishes/thornback-cowfish)*
*Updated: August 11, 2026*