Thornback Cowfish

The Thornback Cowfish is a smaller and more manageable member of the cowfish family, reaching a maximum size of about 9 inches. It features the characteristic boxy, armored body plan of all cowfish, with two forward-pointing horns above the eyes and a distinctive backward-pointing spine on the dorsal ridge near the tail, which gives the species its common name. Its coloration ranges from yellow-green to olive, often with scattered blue spots or lines, and its overall appearance is both endearing and slightly comical as it hovers through the water column.

In the wild, the Thornback Cowfish inhabits coral reefs, lagoons, and seagrass beds throughout the Indo-Pacific, where it feeds on a variety of benthic invertebrates, algae, and small organisms. It is typically found at moderate depths and tends to be a solitary species, though juveniles are occasionally encountered in small groups among sheltered reef areas. Its rigid carapace provides excellent protection against most predators, but its slow swimming speed makes it vulnerable to ambush predators.

Despite being one of the smaller cowfish species, the Thornback Cowfish still carries the family's trademark defense mechanism: the ability to release ostracitoxin when severely stressed. This means all the same precautions that apply to larger boxfish and cowfish must be observed. A minimum tank size of 125 gallons is recommended, with peaceful tankmates, stable water conditions, and careful handling during any transfers. The Thornback Cowfish makes a delightful aquarium inhabitant for the informed keeper, displaying curious behavior and quickly learning to associate its owner with food.