Reasons for Acro crab moving?

I bought two new acro Frags recently. One five days ago, the other four. They both had acro crabs,one in each frag and one is larger than the other. The Frags are at the bottom of my tank in fairly close proximity of eachother,still acclimating. I fed the fish and corals last night and when inspecting the tank during a wake-up bathroom break I noticed the larger acro crab was no longer hosting it's acro. And instead, the smaller of the two that was originally on the yellow bottlebrush moved to the other frag I can't find the crab anywhere. I don't think my fish got him- 2 Ocellaris 2" each, velvet damsel 2", royal gramma 2", 1 1/2" spotted mandarin. I doubt he'd die after feeding so vigorously only a few hours earlier on anything that landed on the frag.

You can see the larger of the two in this pic and this is the frag he was hosting


Here's the yellow bottlebrush that used to house the smaller crab, bit has since yesterday, moved out.


Any ideas? Not on my other corals either. I have another small acro colony that's a bit higher up and over in the tank but that's it for Acro's.

 

I have had them do the same thing Nismo, switch corals and disappear. Sometimes they were just molting somewhere and another time I never saw the crab again. I can see one actively eat when I target feed the corals the other never eats any food I provide.

 

Thanks...Guess I'll just have to keep an eye out then.At least I still have one.He's a tiny guy though.Wonder if he eats RB's .

 

My RB problems are going to be gone soon.

 

Good to hear!

 

I have two acro crabs. One disappeared and I haven't seen him since, and the other loves for me to spot feed in shrimp. He's so funny - he climbs to the top of the acro and stretches up his arms at the feeding tube.

 

Actinics went out just over an hour ago, but I've had the TV on so it isn't pitch black. Just shone a flashlight in there and HE'S BACK!!! Don't know where he was but it's in the same frag as it was before. Now I wonder if they can both occupy the same frag peacefully or will the smaller one go back to the bottlebrush?

KC...mine did the same thing while I was spot feeding last night before the disappearing act! Pretty cool to watch and know that I'm doing something good for him !