The Orange-lined Triggerfish, Orange-striped Triggerfish or Undulated Triggerfish (Balistapus undulatus) is a triggerfish

Triggerfish

Triggerfishes are about 40 species of often brightly colored fishes of the family Balistidae. Often marked by lines and spots, they inhabit tropical and subtropical oceans throughout the world, with the greatest species richness in the Indo-Pacific...

 of the tropical Indo-Pacific

Indo-Pacific

The Indo-Pacific is a biogeographic region of the Earth's seas, comprising the tropical waters of the Indian Ocean, the western and central Pacific Ocean, and the seas connecting the two in the general area of Indonesia...

area. It is the only member of the genus Balistapus. They reach a maximum size of about 30 cm. They feed on coral, crabs and invertebrates. They are found up to around 50 m deep in tropical waters.

In the Aquarium

Balistapus undulatus is a hardy member of a saltwater aquarium. It however has a reputation as one of the meanest fish in the aquarium trade. Sometimes young individuals will accept tank-mates but an owner should expect this fish to kill most fish and invertebrates that share its aquarium. Serious consideration should therefore be made for keeping this fish alone. The minimum tank size to keep a small fish alone is 190 L. It is a slow growing fish, but as it gets older it will likely need a larger aquarium.