Longhorn Cowfish (Lactoria cornuta) Care Guide
An unmistakable fish with a bony box-like body and two horn-like projections from its forehead. Swims by sculling with its tiny fins in a uniquely comical hovering motion.
Compiled by Aquairi from published sources · Published · Updated
Overview
Lactoria cornuta is a species in the family Ostraciidae. An unmistakable fish with a bony box-like body and two horn-like projections from its forehead. Swims by sculling with its tiny fins in a uniquely comical hovering motion. Can release a toxic substance (ostracitoxin) when severely stressed, potentially killing all tankmates. Best kept in a species-specific or carefully managed FOWLR system.
Taxonomy
- Family: Ostraciidae
- Genus: Lactoria
- Scientific name: Lactoria cornuta
- Other names: Horned Boxfish
- Origin: Indo-Pacific
Habitat
Lactoria cornuta is a boxfish of shallow Indo-Pacific reefs, lagoons and seagrass, named for the horn-like projections above its eyes. It blows jets of water at the sand to uncover invertebrates and, when stressed, can release a toxin (ostracitoxin) harmful to tankmates.
Tank requirements
- Minimum tank volume: 400 L
- Temperature: 24-27 °C
- pH: 8.1-8.4
- Salinity: SG 1.024-1.026
- KH: 8-12 dKH
- Water flow: low
- Adult size: 20-45 cm
- Lifespan: 8-15 years
- Difficulty: intermediate
Diet
Classified as omnivore. Recommended feeding frequency: 2-3x daily. In captivity, offer a varied diet appropriate to the species — quality prepared foods supplemented with frozen or live items of suitable size.
Compatibility
- Temperament: peaceful
- Position in tank: middle
- Compatible tank mates: Peaceful Tangs, Peaceful Wrasses, Gobies
- Avoid with: Aggressive Fish, Nippy Fish, Corals, Invertebrates
Reef compatibility
Generally classified as reef-safe with caution: may disturb other sessile invertebrates, sting neighbouring corals or prey on small ornamental shrimps, so placement and tankmates need consideration.
Breeding
- Breeding strategy: egg-scatterer
- Breeding difficulty: advanced
Longhorn Cowfish Breeding Guide
Overview
Lactoria cornuta forms harems of three to four females per male, with females generally larger than males. It reproduces by open-water spawning, releasing pelagic eggs and larvae, a strategy that cannot be reproduced in a closed aquarium. The notes below describe natural reproduction rather than a captive protocol.
Spawning Behavior & Trigger
Paired courtship occurs just before or after sunset, and females spawn shortly after sunset, or during the day when there is heavy cloud cover. The spawning season runs from February through early October. The harem structure means a single male spawns with the several females in its group.
Egg & Fry Care
Both the oval eggs and the resulting ichthyoplankton are pelagic, developing in open water. The larvae gradually develop the boxlike carapace characteristic of adults. This drifting, open-water early life history is the reason the species is not reared by hobbyists.