part of anal fin missing

[Aquaria]

well i got this mccosker wrasse a couple days ago and for the first day he kept all his fins shut, was shy, stayed in his cave and slept/hide for most of the day. now hes out and about in the moonlight and his anal fin is wide now. i noticed part of it is gone and im wondering if i should be worried. will it grow back? he was eating yeaserday before he went back into his cave and hes looking for food now. only thing i have in the tank is a pom pom crab and snails