Weird, I was looking at my tank last night and I found a new crab !!! must be a pest ? It's all black / Dark in color and tend to hide between the crack of the live rock.....have not added any LR in that tank since August so my guess it's been there since the beginning ! Anyone has an idea how to catch this bugger ? I've tried the inverted bottle trick with a piece of fish and I ended up with a ton of Nassarius Snail but no crab.
try to take pictures
If its dark or black & hair very very bad take it out before it gives you pain a butt :)
I mean hairy crab lol
I noticed a small black hairy crab in the cracks of my LR about 2 months after setting it up. He moved slowly and always in a recessed, hard to get to spot. I ended up just pulling the liverock out, and even then he hid int he nook and crannies of it. I ended up having to pry him out... It was an epic 5 minute battle, but I am glad to report, I won.
I've always had luck pulling the rock, and spraying it with fresh hot water... sneaky little guys usually come out running.
to catch him, try the using a Mason jar with food at the bottom. Leave the opening at the top with the jar on a slant. Crabs will crawl in but not be able to climb out. If you place it near where it lives, you should catch him.
Snails will be able to get out.