Description:

Dorsal spines: 3; Dorsal rays: 24-27; Anal spines: 0; Anal rays: 20-24.

Dark blue-green, dark green to brownish green body with oblique curved orange lines on posterior head and body; an oblique band of narrow blue and orange stripes, 
underlined with a black stripe,  from around the mouth to below the pectoral fin. No groove in front of eye.  Adult male with no bands on dark snout. A large black 
blotch surrounding 2 rows of peduncular spines.  Caudal fin orange. Rays of pectoral, soft dorsal and anal fins orange.

Maturity: Lm unknown. Range unknown. Max Length: 30.0 cm TL.

Reef associated, occurs in coral-rich areas of deep lagoons and seaward reefs to 50m depth. Territorial nature. Feeds on diverse benthic organisms including algae, 
echinoderms, fishes, molluscs, tunicates, sponges, and hydrozoans. Spawning behaviour may involve loose aggregations and nesting occurs in channels. Eggs are laid 
in a single spongy cluster in a shallow excavation in rubble or sand. Nests are guarded by adults.

This species is not protected or subject to fishery regulations. It is caught in the fish trap and hand line fisheries, but is an uncommon component of the catch.

Can give severe bite and inflict wounds with peduncular spines.

Bray, D.J. (2018).  Balistapus undulatus in Fishes of Australia. http://fishesofaustralia.net.au/home/species/760 (30/10/18).
Froese, R. & D. Pauly. Eds. (2018). FishBase  https://www.fishbase.de/summary/Balistapus-undulatus (30/10/18)
Smith, M & Heemstra, P Eds. (1999). Smiths’ Sea Fishes Edition 6. Springer-Verlag Berlin Heidelberg 10.1007/978-3-642-82858-4

Nevill, J.E.G. (2019). Balistapus undulatus, Orange-lined triggerfish. Seychelles Seatizens. www.seatizens.sc. https://seatizens.sc/species/balistapus-undulatus-park-1797/  (Edited 06/10/21).