Best way to catch a crab

markc212

Member
Got what I think is a stone crab as a hitchhiker from a piece of live rock. It's got black claws so I want to get it out of the DT. What's the best way to catch it? Here's what I've tried so far:
1. Put a piece of shrimp in a tilted glass near where the crab likes to hang out. He does try to creep down to get it, but never gets to the point of letting go from the nearest rock. Though in the process, I've caught just about every hermit crab in the tank. I guess hermits aren't quite as smart as this crab.
2. Put a piece of shrimp in a net to see if the crab will venture into the net to get it. Doesn't even seem interested in climbing into the net.
3. Tried to put a piece of shrimp on a stick to see if I could get him to grab on and move him to a cup or container. He just rips the shrimp right off the stick and scampers away.
4. I've heard that it's possible to take the whole rock and put it into a bucket of high salinity water. This might drive out the crab without killing the corals. This actually worked with a larger Black Mithrax that was on the same rock. But, this stone crab just stayed put.
If I were desperate enough I would consider taking out the rock and drying him to death, but I've got a bunch of small corals on this rock.
This guy is driving me nuts. He's small, fast, strong, and worst of all, he's extremely cautious. He never seems to venture off the rock and doesn't really wander around at all. Any other suggestions?
 

btldreef

Moderator
Take the rock out of the tank, place it in a bucket and leave it in the air for a few minutes, this usually will entice the crab to come out.
What type of corals are on the rock? If they're expensive or large colonies of SPS I wouldn't do the out of water method so willingly.
I had a Xanthid that I absolutely could not catch. I finally took the rock out, and stabbed the hole I knew he was in a million times with a screw driver. Wasn't fun, but I needed him to stop killing my critters.
If you can get the corals off this rock, or you're willing to sacrifice them, mix up a batch of ultra high salinity water (1.030 or more, the higher the better), place a piece of eggcrate in the bottom on a bucket (elevate it up a little if you can) and place the rock on the eggcrate in the water. The higher salinity will usually draw the crab out of the rock in search of refuge. It will then fall through the eggcrate and voila, you've got your rock and your crab, separately.
 

markc212

Member
So I tried to be somewhat peaceful about this and was unsuccessful. Removed the rock out of the water and put it on some egg crates. After 10 minutes, the crab still wasn't coming out. So, I followed the advice on another thread and took a long screwdriver to the holes in the rock. Using a flashlight, I could see where the little bugger was, and I essentially chased him out of the hole with the screwdriver.
Here are some pics of the bane of my existence. Should I have been concerned? Definitely not an Emerald, and everyone keeps saying that black claws = get him out of the tank.
 

btldreef

Moderator
Oh yes, good thing you got him out.
Sharp black tipped claws = BAD CRAB
If I had to identify it, I'd say Xanthid sp.
The screw driver method is effective, at least you went about it more humanely than I had to resort to...
 
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