posed ▁sh or elines . ▁It ▁toler ates ▁sal inity ▁concentr ations ▁of ▁ 0 – 1 9   pp t ▁and ▁pre fers ▁water ▁temper atures ▁of ▁. ▁Pop ulations ▁may ▁surv ive ▁temper atures ▁of ▁ ▁over ▁winter , ▁but ▁not ▁without ▁substantial ▁mort ality . ▁ ▁Food ▁H . ▁anom ala ▁is ▁an ▁opportun istic ▁om n iv ore ▁that ▁fe eds ▁primarily ▁on ▁zo op l ank ton , ▁particularly ▁cl ad oc er ans , ▁but ▁also ▁cons umes ▁det rit us , ▁ph y top l ank ton ▁( part icular ly ▁green ▁alg ae ▁and ▁di at oms ), ▁and ▁insect ▁lar va e , ▁and ▁is ▁occasionally ▁can n ib al istic . ▁Young er ▁individuals ▁feed ▁mainly ▁on ▁ph y top l ank ton . ▁The ▁proportion ▁of ▁zo op l ank ton ▁consum ed ▁in ▁the ▁my s id ' s ▁di et ▁increases ▁with ▁its ▁body ▁size . ▁A ▁blo ody - red ▁my s id ▁fe eds ▁using ▁its ▁thor ac ic ▁lim bs , ▁either ▁by ▁capt uring ▁pre y ▁with ▁its ▁end op ods ▁or ▁by ▁removing ▁food ▁particles ▁from ▁its ▁body ▁that ▁are ▁filtered ▁from ▁incoming ▁curr ents ▁by ▁its ▁ex op ods . ▁ ▁Be hav iour ▁ ▁Ind ividual s ▁remain ▁near ▁prof und al ▁sed iments ▁during ▁the ▁day , ▁migr ate ▁in ▁sw ar ms ▁to ▁the ▁upper ▁water ▁column ▁at ▁tw il ight , ▁then ▁return ▁to ▁the ▁prof und al ▁zone ▁at