I agree with Untamed. The arms falling off sounds a little fishy to me, too. Something's chasing him in there. Ours would molt, like all the other shrimps, but his arms were always there. He was a good bristleworm eater, and scavenged for scraps all the time. We hand fed him as well, so he was quite interactive.

I don't see him a lot but one day he is missing an arm and two days later it is back... maybe I just can't see it at times. I tried target feeding him but he does his own thing. I did notice when he came out for food, my rotten satanic damsel fish (tried to catch and forever now) took a good shot at him. He has bitten me and it is not enough to rip off an arm though. This shrimp is really quite large, and a damsel would not be abler to take him. I see him come out and none of the fish even bother with him. They would rather swim the other way to be honest.