name that crab?

[unwritten law]

So in my 20 gallon reef I have been loosing snails and hermits. I thought it was cause i just bought them within a month or two and my tank was fairly hot (85 degrees at times). But then when I went to move a rock to look for my pistol shrimp I found this guy who I assume also ate my pistol shrimp. No idea how long e has been there but he was at least friendly to my fish.... for the time being. Since I have gotten rid of him. I'd say he was almost an inch across.

 

[quaddity]

Some kind of mithrax crab. Best to get it out now that's for sure. I highly doubt it ate your pistol shrimp or snails/hermits. The heat probably killed them. The pistol shrimp could kill that crab without a problem. When they are that size the crabs aren't much of a problem they just scavenge. But when they get bigger they can reek havoc. I had a big one eating corals.

 

[unwritten law]

he was pretty big.. bigger than the shrimp (which is still a baby) but I just found the shrimp so you are right, he didn't kill him. but i just re supplied my snail/ hermit population so that's good.

I am just shocked that he managed to stay hidden so long in a 20 gallon tank. He was about the size of my full grown emerald crab I had a while back.