Spotted Boxfish

Geographical Origin and Habitat: Tropical Indo-Pacific, from East African coasts to Hawaii and French Polynesia. Inhabits shallow, protected coral reefs and lagoons rich in corals and algae.

Taxonomy and Morphology: Belongs to the family Ostraciidae. Reaches 25 cm in length. Characterized by an unusual, rigid box-like carapace formed by fused hexagonal bony plates, with openings only for the mouth, eyes, and fins.

Social Behavior: Shy and solitary fish. Males are highly territorial and aggressive toward other males of the same species, while females are more tolerant.

Coloration and Sexual Dimorphism: Strong sexual dimorphism. Males exhibit a bright blue coloration on their flanks with golden spots, and a black back with white spots. Females and juveniles are entirely black or dark brown with small white spots all over the body.

Aquarium Setup: Requires large tanks (at least 750 liters / 200 gallons) to dilute potential toxins and provide free swimming space. Lots of live rock for grazing and hiding spots, but without sharp obstacles that could damage its delicate body.

Diet and Feeding: Benthic omnivore. In the aquarium, it requires a varied diet: algae, frozen foods (mysis, krill, clam pulp), and sinking pellet foods. Avoid floating food to prevent air ingestion.

Water Quality: Excellently filtered and stable water. Specific gravity 1.020-1.026, pH 8.0-8.4, dKH 8-12. Sensitive to nitrate accumulation and requires a strong protein skimmer.

Compatibility and Cohabitation: Not considered reef-safe as it nips at corals and sessile invertebrates. Cohabits with calm and non-aggressive fish; active or boisterous tankmates easily stress it.

Aquarium Breeding: Reproduction in the aquarium is extremely difficult and not documented at the hobbyist level. They are pelagic spawners, releasing eggs that float on the water surface.

Risks and Diseases: Extreme risk: under high stress, illness, or death, it releases a lethal toxin (ostracitoxin) that can decimate all fish in the tank. High-quality activated carbon must be run constantly.