Red crab like living inside my Rainbow Pectinia

[Jx3069]

Hey guys, need some help ID'ing this one. I was enjoying my tank tonight and I noticed something moving in my Rainbow Pectinia, upon closer look, it seems like a red crab like critter living inside the hole. It's really small so hard to get a good picture, but I did the best I can. The hole is very tiny, no more than 1 to 1.5mm so the critter is probably just as small. I don't want to freak out yet, until it's ID and if I'll have to dig him out. I know the picture isn't clear, but I hope someone ran into this before and can give me a rough idea.

 

[Auto-pilot]

Looks like a gall crab. It might be something different but that's what it looks like from the picture

 

[reef lover]

+1

 

[Jx3069]

Thanks guys! I'll probably leave him be and monitor

 

[Jberg]

I've seen pictures of small hermit crabs living on Cristmas tree coral (coral hermits). Rare but very cute. That would be neat if it was one of those.