Mobile Bay Reef Keepers

My zooanthids have been dissapearing for some time and I didn't know why. I had noticed I had a small crab similar to an emerald crab, but not green. They are very small, probably about the size of a dime. I had noticed that it was picking at the zoo's. I watched him for some time, then about 2 months ago I was able to catch the little f**k with some tweezers. Then a few days later I pulled out another one. I continued to watch my zoo's dissapear and decided to pull out my electric blue hermit crab, thinking he may be the problem. I continued to watch my zoo's die and almost gave up. Then friday afternoon, I saw antoher of these little crabs and caught him and put him in my refuge. Then saturday I noticed my protein skimmer full of foam and knew something was wrong. I had recently bought a large cucumber for my refuge and noticed that something had attacked him. It almost looked as if someone had taken a knife and sliced him down his sides on both sides. I have attached a pic of the little crab I pulled out - this one making the third I have removed from the tank. Do you think this is the killer of my zoo's? Do you think this little guy would have attacked my cucumber or do you think the hermit may have done it. The only other things in my refuge are smails and a queen conch. Please help!!!

From the pics it looks similar to one of the Xanthid crabs. They have variable color and patterning, but tend to have spatulate claws, similar to Mithraculus. In general, they tend to eat most sessile life they can find, so that is most likely what is eating the zoanthids. As far as the cuke is concerned, the jury's out. I am a little skeptical to think that that small a crab did that much extensive damage to the sea cucumber, but i suppose it is possible.

It seems hard to beleive to me to that that little crab could have done that to the cucumber. The cucumber was probably 7 or 8 incehs long and the cuts down his sides were probably 3 or 4 inches (almost identical on both sides). At one time, I remember seeing the electric blue hermit crab on top of the cucumber but didn't appear to be bothering him. The best I can tell is that the little crab probably crawled on the cucumbers back and took the left claw and cut the left side, then took the right claw and cut the right side, and back and forth like that until he made two big slices. Like I had said before, the only things in the refuge were those two crabs, snails and a conch.

Anyway, thanks for the identification. I just hope there aren't anymore of them in the tank.

Look for these.

That little thing is creepy looking! Looks like something I'd want to squash with my shoe.