Can an arrow crab eat a bristle worm with 1 claw

[Treenk]

So I bought an arrow crab because I have over 100 little ones running around my 13g. When I got it into the tank I realized it's missing a claw and a leg... he looks like he eats things off the rock constantly, but not sure if he will go for the bristle worms. I read that they can grow a claw back but couldn't find any info on how often they molt or how long the process takes. Any insight would be great.

 

[WVNed]

If it is smaller every 2-4 weeks.