usk , ▁when ▁the ▁light ▁levels ▁make ▁it ▁difficult ▁for ▁pred ators ▁to ▁see ▁and ▁feed ▁upon ▁the ▁eggs . ▁ ▁Court ship ▁ ▁As ▁cor al ▁tr out ▁aggregate , ▁males ▁establish ▁temporary ▁territ ories . ▁They ▁then ▁try ▁to ▁ent ice ▁females ▁into ▁their ▁territ ories ▁to ▁spawn ▁by ▁means ▁of ▁elaborate ▁court ship ▁displays . ▁As ▁part ▁of ▁this ▁court ship ▁rit ual , ▁male ▁cor al ▁tr out ▁display ▁their ▁fins ' ▁dark ened ▁edges , ▁which ▁can ▁be ▁switched ▁on ▁and ▁off ▁almost ▁instantly . ▁The ▁male ▁approaches ▁a ▁female , ▁which ▁is ▁usually ▁close ▁to ▁the ▁bottom , ▁with ▁his ▁body ▁t ilt ed ▁at ▁ 4 5 – 9 0 ° ▁( al most ▁lying ▁on ▁his ▁side ▁in ▁the ▁water ) ▁and ▁repeatedly ▁qui ver ing ▁length wise ▁and ▁sh aking ▁his ▁head ▁from ▁side ▁to ▁side . ▁He ▁passes ▁close ▁to ▁the ▁female ' s ▁head ▁or ▁body ▁with ▁either ▁the ▁top ▁or ▁unders ide ▁of ▁his ▁body . ▁This ▁process ▁is ▁repeated . ▁ ▁Sp aw ning ▁r ush ▁ ▁Sp aw ning ▁r ush es ▁occur ▁after ▁this ▁court ship ▁behavior , ▁if ▁the ▁female ▁agre es . ▁During ▁a ▁sp aw ning ▁r ush , ▁the ▁male ▁and ▁female ▁sw im ▁rapidly ▁towards ▁the ▁surface , ▁where ▁they ▁release ▁s perm ▁and ▁eggs ▁into ▁the ▁water ▁as ▁they ▁quickly ▁turn . ▁The ▁cloud ▁of ▁s perm ▁and ▁eggs ▁released ▁during ▁a ▁sp aw ning ▁r ush ▁is ▁not ▁easily ▁seen ,