I have a decorator crab thats messing with my rock work in my 58 g reef. I thought about getting rid or him or putting him in with my mantis. He has a newly added 12 g eclipse. There is nothing in there with him. He is a little guy...about 2.5 inches. He has killed a couple of mud minnows that i had put in to test water quality. They were 3 times his size. I doubt the crab could hurt him since he's pretty slow moving but i don't want him beaten to death either. Does anyone thing this is a decent idea?