fish ▁( B ol b omet op on ▁mur ic atum ) ▁is ▁the ▁largest ▁species ▁of ▁par rot fish , ▁growing ▁to ▁lengths ▁of ▁ ▁and ▁we igh ing ▁up ▁to ▁. ▁ ▁It ▁is ▁found ▁on ▁re ef s ▁in ▁the ▁Indian ▁and ▁Pacific ▁O ce ans , ▁from ▁the ▁Red ▁Sea ▁in ▁the ▁west ▁to ▁Sam oa ▁in ▁the ▁east , ▁and ▁from ▁the ▁Ya ey ama ▁Islands ▁in ▁the ▁north ▁to ▁the ▁Great ▁Bar rier ▁Re ef , ▁Australia , ▁in ▁the ▁south . ▁ ▁Other ▁common ▁names ▁include ▁b ump head ▁par rot fish , ▁hum p head ▁par rot fish , ▁double - head ed ▁par rot fish , ▁buff alo ▁par rot fish , ▁and ▁giant ▁par rot fish . ▁ ▁It ▁is ▁the ▁only ▁species ▁in ▁the ▁monot yp ic ▁genus ▁Bol b omet op on ▁and ▁is ▁the ▁largest ▁her b iv orous ▁fish ▁inhab iting ▁cor al ▁re ef s . ▁ ▁Species ▁description ▁ ▁Un like ▁wr ass es , ▁it ▁has ▁a ▁vertical ▁head ▁profile , ▁and ▁unlike ▁other ▁par rot fish es , ▁it ▁is ▁uniformly ▁covered ▁with ▁scales ▁except ▁for ▁the ▁leading ▁edge ▁of ▁the ▁head , ▁which ▁is ▁often ▁light ▁green ▁to ▁p ink . ▁Primary ▁phase ▁colour ation ▁is ▁a ▁d ull ▁gray ▁with ▁scattered ▁white ▁sp ots , ▁gradually ▁becoming ▁uniformly ▁dark ▁green . ▁This ▁species ▁does ▁not ▁display ▁sex - associ ated ▁patterns ▁of ▁color ▁change . ▁The ▁adult ▁develop s ▁a ▁bul b ous