Crab in my Brain? WARNING HUGE PICTURE!
 

..coral, that is.

I have a Lobophyllia and I recently spotted what I think is a crab embedded in the folds of the brain coral. The claws are VERY small compared to the body size. When it starts to creep out it definitely tears the brain's flesh, but so far, the area doesn't seem to be dying or diseased. My question is: is this crab symbiotic, a pest, harmful or harmless?

In the picture below, it's the largest 'hole' at the bottom right corner. (I told you the picture was big!) You can see the creature's head and one leg.

http://members.shaw.ca/nemod/aquarium/crabbrain.jpg

Looks like it might be "Rippin" it's way out! (Sorry I couldn't resist.)

This is one of the strangest things I've seen recently.

I have the exact same thing in what i think is a moon coral or favite. So far the corals done great...

Well, last night I saw a second, VERY tiny, whitish crab doing the same thing - burrowing into the flesh of the brain. But by the next morning there was no trace of the hole anymore. Well it doesn't seem to bother the coral, so I guess I won't worry about it.

Could this be it?
 

I discovered this crab in my tank a couple of months ago and I have been meaning to post a pic and see if anyone knows what it is. From the little bit that I could see in the picture of your first post I thought they looked a little similar.... My crab is not in any of my corals but he does go in and out of a rock with a little hole. He is very shy and only comes out just before lights out or at night. I have seen him many times now as he is getting a little braver. So far all I have ever seen him eating is algae, and detritus. I have a pic, sorry but my camera only has 4X zoom so it's not the best.......

http://www.themomos.net/images/P1020396.jpg

I can't say if the crab in my brain coral is the same as yours, Keana. It only sticks a bit of it's head out (when I'm looking). It most probably comes out at night. I'm thinking of trying to extract this crab from the coral. If I am successful I'll try to post a picture of the crab. I just don't want to hurt the coral while doing so.

I can't see a thing! You think you could circle it in photoshop or something.... ;)

OK I've altered the image to make it a bit easier to find the crab hole :mrgreen:

wow, nice brain

Extracted the crabs!
 

OK, I was able to take out the crabs as they were emerging at night.

I honestly don't know if the big invertebrate that I pulled out is a crab! The really tiny one with the green back looks like a crab to me. They are both very slow moving creatures. Anyway, the larger of the two was definitely growing in the brain coral for quite some time because after I took it out, it left a substantially deep hole (about 1 cm). I hope the brain coral will just grow over and close this hole up.

If anyone can help identify what I pulled out, that would be great.

..and here are the pictures:

http://members.shaw.ca/nemod/aquarium/crab01.jpg

http://members.shaw.ca/nemod/aquarium/crab02.jpg

http://members.shaw.ca/nemod/aquarium/crab03.jpg

http://members.shaw.ca/nemod/aquarium/crab04.jpg