Blue Boxfish Male EXPERT (Ostracion Meleagris)

Also Known As: Blue Boxfish, Blue Trunkfish

Compatibility and Behavior
The male Blue Boxfish is a genuine showpiece. The body is a vivid cobalt to sky blue, scattered with a constellation of lighter spots and fine reticulated markings that really stand out under reef lighting. That angular, box-shaped body paired with small rounded fins gives it the classic hovering swimming style that boxfish are known for, and subtle yellow or pale edging on the fins and around the mouth adds extra character up close. Behavior-wise, this is a slow-moving species that can be peaceful with many larger, non-aggressive tankmates, though it tends to struggle alongside fast, boisterous, or nippy fish that might harass it or beat it to the food. Like other boxfish, it falls into the reef safe with caution category. Some individuals will pick at fleshy invertebrates or sponges, and a stressed or continually chased fish is more likely to act defensively. Settled into a calm, stable community, a male Blue Boxfish often becomes a genuinely engaging pet, cruising the rockwork and front glass with real curiosity and responding to its keeper at feeding time.

Aquarium Requirements
A mature, spacious marine aquarium is the right home, offering both open water for slow, deliberate swimming and plenty of rockwork to explore at a relaxed pace. A tank with a generous footprint paired with gentle to moderate flow lets the fish maneuver comfortably without getting pushed around by strong currents. Peaceful tankmates, stable conditions, and patient acclimation all matter a lot with this species, since boxfish are sensitive to stress and to swings in water quality. Aquascape with shaded areas, caves, and overhangs where the fish can retreat when startled, alongside clear swimming lanes along the front of the rockwork where it can forage and interact. Offer a varied diet of chopped meaty foods, frozen mysis shrimp, and quality omnivore pellets to keep body condition strong and encourage the natural grazing and investigative behavior that makes these fish so fun to keep.

One important note on boxfish toxicity: like all Ostraciidae, the Blue Boxfish can release a potent toxin (ostracitoxin) when severely stressed or dying. In a closed aquarium, this can wipe out the entire tank, so it's worth having activated carbon and emergency water change supplies ready.

Specifications
Approximate Size: 4-6"
Diet: Omnivore (they love chopped squid)
Origin: Indo-Pacific (exact locality may vary by supplier)
Care Level: Expert (requires stable conditions, peaceful tankmates, and careful feeding)
Reef Safe: With caution (may nip at some invertebrates or soft corals)
Temperament: Peaceful
Minimum Tank Size: 120 gallons
Special Considerations: Can release a tank-wiping toxin (ostracitoxin) when severely stressed or dying; sensitive to water quality and stress; best housed with peaceful tankmates