I have done reading on this coral alot this week, i know that they do tend to have crabs live in them, im wondering if anyone can describe them to me. I see 3 very small redish looking crabs that seem to have a soft exterior. Is it safe to place these in my tank? do i have to worry about them moving and stalking fish/corals. they are rather small. answers ASAP. as it is dripping in now.