Marcocoeloma trispinosum (red sponge decorator crab) experience?

[Tired]

Just ordered one of these from KP Aquatics. I was originally planning to put it in a small 'fuge attached to my main tank, but I'm now considering putting it in the main tank. 

 

Now, obviously this is a decorator-type crab, which will snip at macroalgae and soft corals. Not a huge deal for me- I can put small frags of zoas up on a frag rack, out of reach, until the frag is large enough to survive losing a couple polyps. Barring that, will these guys hurt anything else? Fish, shrimp, snails? 

 

If I put one of these in a tank with xenia, will it wind up transplanting xenia stalks off their island and onto the main rockwork? 

[Tired]

Having now had one in hand, I can say that they eat feather caulerpa, and that they're surprisingly soft to the touch with all the little hairs they attach things to. I don't know anything more about them.