
Source: Wikimedia Commons
Lactoria cornuta
A boxfish relative with two horns on its head and a cube-shaped body. Under severe stress it releases pahutoxin from its skin and can kill tankmates, and it reaches 46cm, so it is for advanced keepers.
The Longhorn Cowfish (Lactoria cornuta) is an ostraciid found from the Red Sea and East Africa to the Marquesas and north to southern Japan. It enters sheltered bays, harbours and brackish river mouths, living at 1-100m. Four horns, two above the eyes and two at the rear, and a boxy yellow-brown body with pale blue spots make it unmistakable; adults are solitary while juveniles form small groups. It blows jets of water into sand to expose benthic invertebrates and also eats algae and foraminiferans. Maximum 46cm. Keep at 22-26C, pH 8.1-8.4 and SG 1.020-1.025 in a tank of 950L or more. It is peaceful but slow to swim and slow to eat, so never house it with fast feeders. The critical risk is pahutoxin, released from its skin mucus under severe stress or at death, which can wipe out every fish in a closed tank. Minimise shipping and netting, add it to the tank first and keep it alone; it does not tolerate its own kind. IUCN: Least Concern.
Source: Wikipedia (CC BY-SA 4.0)
The Longhorn Cowfish grows to Up to 46cm.
The ideal temperature for the Longhorn Cowfish is 22〜26℃.
Origin
Indo-Pacific (Red Sea and East Africa to the Marquesas, north to southern Japan)
Size
Up to 46cm
Temperature
22〜26℃
Sources: LiveAquaria / FishBase
Edited & verified by: BreederDirect editorial team
The taxonomic, regulatory, and husbandry data on this page are compiled and verified against the authoritative primary sources below.
Sources: CITES Appendices (species not listed) / IUCN Red List
Regulations may change. Always verify the latest information with the relevant authorities.
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Frozen brine shrimp, mysis, chopped clam and shrimp, seaweed
Releases pahutoxin from the skin under severe stress or at death, which can kill every tankmate. Never net it; minimise moving.
950L or more, added first and kept alone. Run carbon and a skimmer at all times as insurance against toxin release.
22-26C, pH 8.1-8.4, SG 1.020-1.025. Sudden changes stress it, so stability comes first.
Frozen brine shrimp, mysis, chopped clam and shrimp, and seaweed in several small feedings. It eats slowly, so check food reaches it.
No conspecifics. Avoid fast swimmers and food thieves. Leaves corals alone but digs out small animals from the sand.
Advanced. This is an advanced-level species. It requires specialized equipment and advanced husbandry skills with precise environmental control.
The ideal temperature for Longhorn Cowfish is 22〜26℃. Avoid sudden temperature changes and maintain a stable environment.
Longhorn Cowfish typically reaches Up to 46cm as an adult. Size may vary depending on care conditions and individual genetics.
Longhorn Cowfish feeds on: Frozen brine shrimp, mysis, chopped clam and shrimp, seaweed. Aim for a balanced diet with appropriate feeding frequency.
The price of Longhorn Cowfish varies significantly depending on morph, size, and lineage. Check our market price page for the latest pricing information.
Last updated: September 15, 2026