All fish / Ostraciidae

Longhorn Cowfish

Lactoria cornuta

Also known as longhorn cowfish, long-horned cowfish, cowfish, horned boxfish, horn cowfish, caution cowfish, longhorn boxfish, ปลาวัว, コンゴウフグ, ikan buntal kotak tanduk, 角箱鲀, 长角牛鱼

A boxfish with a rigid bony carapace, long forward-pointing horns above the eyes and a pair of spines at the rear, coloured yellow to olive with blue spots. Juveniles are small and comical, and keepers value its curious nature and readiness to beg for food.

Care at a glance

Care level

Hard

Temperament

Peaceful

Adult size

30 cm

Temperature

24 to 28 °C

pH

8.1 to 8.4

Smallest tank

700 litres

Keep as

Single specimen; avoid keeping two together

Diet

Omnivore: mysis, krill, chopped shellfish and squid, plus algae and spirulina based foods

Swims

Middle of the tank

Lifespan

8 to 10 years

Water

Marine (saltwater)

Wild range

Indo-West Pacific, from the Red Sea and East Africa to the Marquesas, southern Japan and Australia

Breeding

Pairs spawn pelagic eggs near the surface at dusk in the wild. Captive breeding in home aquariums is very rarely achieved.

Good to know

It can release a toxin (ostracitoxin) when stressed or dying that may wipe out a whole tank, so it needs a big, well filtered system without aggressive or nipping tankmates. Small juveniles grow to around 30 to 45 cm and need a very large aquarium.