Lactoria cornuta

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Latin name Lactoria cornuta - (Linnaeus, 1758)
Local name Longhorn Cowfish
Family Ostraciidae - Lactoria
Origin East Indian Ocean, West Indian Ocean, Australia, Japan, The Red Sea
Max length 45 cm (17,7")
As aquarium fish
Minimum volume 1500 cm (396 gal)
Hardiness Delicate
Suitable for aquarium Experience, preparation and extra care required
Reef safe Reef safe with luck
Aggressiveness Mostly peaceful but might be aggressive towards similar species
Recommended Macroalgea (Eg. seaweed / nori)
Small crustaceans (Krill, mysis, artemia...)
Mostly Other invertebrates
Soft coral
Large polyp stone coral (LPS)
Maybee Larger crustaceans (Shrimp, crabs...)
Beware of
Eats tubeworms

This species likes to eat tubeworms.

Threat towards invertebrates

This species likes eating crustaceans, small bivalves and the like.

Poisonous skin

This species has a toxin in its skin, which it releases when highly stressed or dying.

This poison can kill all the aquatic life in the aquarium, if unlucky.

Demand a very large aquarium when fully grown

This species needs a very large aquarium when fully grown.

Exactly how big the aquarium should be is hard to say, but the size of this species is such, that it cannot normally be kept in a home aquarium.

Keep in mind
Poor maneuverability

This species cannot maneuver in strong currents, especially so when small.

Pay particular attention to the pump’s water inlet as these fish in certain circumstances, can get stuck.


This species often has a fun and interesting personality.

Descriptions and further reading
Family description (Ostraciidae)

Boxfish(Ostraciidae) have a unique square shape and a particular way of swimming.
They have a rather special personality, which one quickly comes to love.

Boxfish live typically off a mixture of algae, coral polyps, zooplankton, and in some cases crustaceans.
They are not normally reef safe and when small will require gentle water circulation.

Boxfish can secrete a poison when stressed or if they die, which can in the worst case, kill the contents of a whole aquarium.
Never use the water the fish was transported in.

Aquarium trade Yes
Distribution Indo-Pacific: Red Sea (Ref. 12541) and East Africa (Ref. 12484) to the Marquesan and Tuamoto islands, north to southern Japan, south to Lord Howe Island (Ref. 9710).
English common names Longhorn cowfish
Long-horn cowfish
Long horned cowfish
Long-horned cowfish
Danish common names Kofisk
French common names Coffre
Poisson vache à longues cornes
References and further reading

About references

Bob Fenner. The Puffers Called Box-, Cowfishes, family Ostraciidae - Wet Web Media - (English)
Richard Aspinall. 2012. Oddballs for the Marine Aquarium - Tropical Fish Hobbyist - (English)