- English Name : Yellow boxfish
- Local Name : Gonu
- Size : Max. 40 cm
- Family : OSTRACIIDAE
- Order : Tetraodontiformes
- Distinctive Characters: Dorsal fin with 9 rays. Anal fin with 9 rays. Pectoral fin with 11 rays. Carapace quadrangular in cross section, the sides concave. Body becoming more elongate with growth. Large adults with a bump anteriorly on snout. Caudal fin rounded.
- Colour: Small juveniles bright yellow with small black spots. Larger fish brownish yellow with one white spot edged in black or rimmed with small black spots on each polygonal plate. Largest fish purplish brown, spots on carapace faint or absent, the grooves between polygonal plates yellow, specially ventrally on cheek. Fins with small dark spots on rays.
- Habitat and Biology: Common on reef edge and slope to depths of about 25 m. Solitary and shy species, always seek shelter below overhangs in the reef. Omnivorous.
- Distribution: Indo-Pacific.
- Remarks: Ostracion cubicus, like other boxfishes produce a skin toxin when alarmed. Previously, recorded
as O. tuberculatus Linnaeus, in the Catalogue of Fishes of the Maldives, Vol. 1, page 102.