Hitchhiker on turbinaria coral

[rustyfox9]

Picked up a smaller polyp turbinaria as a rescue from my local LFS, was a frag from a larger colony that got beat up by a neighboring psamacora, I think. Had it for about six months, always noticed this small hole, figured it was from its past, but the coral's healed around it. Looked like maybe a critter was in there, possibly a barnacle. This morning, feeding the corals, a krill landed right near the hole. Turns out, we've got a tiny crab living in there. Needed a magnifying glass just to spot him, he's that small. Uniformly tan in color, all I can see is the front of his carapace and two tiny claws, no marks, no spots, can't even make out eyes. He's only a couple of millimeters in size. Any ideas what this little guy might be?

[zenoxa]

No pic, like I said - way too small.

Have a look at this link though, might give you an idea of the tiny critters we're dealing with: lionfishlair.com/hitchhiker/hitchhiker.shtml

[rustyfox9]

I'm not gonna get a usable pic, it's just too small and I don't have a macro lens. From what I can see, it looks like some type of gall crab - found some old threads that seem to point in that direction. Now I'm wondering, is it a symbiotic relationship with the turbinaria or is it a parasite?

[rusticore]

I had a similar experience with my turbinaria, where a gall crab made itself at home in a little fold. I left it be for about six months, figuring it was harmless, but then I noticed it was slowly excavating its hole towards the back. That's when I decided to take action. Flushing it out with a blast of fresh water didn't work, and I was worried about the damage it might be causing. Eventually, I managed to coax it out with a piece of wire. I'd recommend removing it, you never know what kind of damage it's doing in there.