▁fore head ▁and ▁the ▁teeth ▁pl ates ▁are ▁exposed , ▁being ▁only ▁partly ▁covered ▁by ▁lips . ▁The ▁species ▁is ▁slow - g row ing ▁and ▁long - l ived ▁( up ▁to ▁ 4 0 ▁years ), ▁with ▁delayed ▁reprodu ction ▁and ▁low ▁re pl en ishment ▁rates . ▁ ▁This ▁species ▁is ▁gre g ari ous ▁and ▁usually ▁occurs ▁in ▁small ▁aggreg ations , ▁but ▁group ▁size ▁can ▁be ▁quite ▁large ▁on ▁sea ward ▁and ▁clear ▁outer ▁l ago on ▁re ef s , ▁exceed ing ▁ 7 5 ▁individuals . ▁ ▁Re production ▁ ▁The ▁green ▁hum p head ▁par rot fish , ▁is ▁sex ually ▁mon och rom atic , ▁i . e . ▁there ▁is ▁no ▁initial ▁or ▁terminal ▁phase ▁in ▁the ▁life ▁cycle ▁of ▁the ▁adult s . ▁The ▁fish ▁spawn ▁pel ag ically ▁near ▁the ▁outer ▁re ef ▁slope ▁or ▁near ▁prom ont ories , ▁gut ters , ▁or ▁channel ▁mouth s ▁during ▁a ▁lun ar ▁cycle , ▁usually ▁sp aw ning ▁just ▁prior ▁to ▁the ▁new ▁moon . ▁They ▁make ▁use ▁of ▁sp aw ning ▁aggreg ation ▁sites . ▁ ▁E col ogy ▁ ▁New ly ▁settled ▁ju ven iles ▁are ▁found ▁in ▁branch ing ▁cor al ▁habit ats ▁( prim arily ▁Ac rop ora ) ▁in ▁shelter ed ▁l ago ons . ▁Small ▁ju ven iles ▁( < 5 0 mm ) ▁are ▁often ▁associated ▁with ▁Dam self ish . ▁Lar ger ▁ju ven ile ▁green ▁hum p head ▁par rot fish ▁are ▁found