Xanthid Crab??? No pics (sorry)

sweatervest13

sweatervest13

Active Member
Last night when looking at my tank (29g) I saw that my Frogspawn was lying on the sand bed. It is usually stuck in a small hole in a rock. I never thought it would fall out as it was in there pretty good. I looked in the hole and saw something moving, it looked small at first about half a cm and then I realized that it was just the arm of the thing. After I got the wife and one of my buddys that was over we stared at the tank for about a half hour in this little hole. You could tell it was a crab but I did not know what kind of hitchhiker I had.
I went to the google machine and pulled up some site that had the normal crabs that you can buy for SW tanks and it was not on the list at all. Googled more and found some info on a Xanthid crab and some images and it looked just like it. I read some threads on SW sites and most said that they might not be a good thing. When we were all noses against the glass on my tank we saw the crab eating small featherdusters/ tube worms. So I made the call to take it out of the tank. I was all ready for a large W/C to deal with some Cyano issues I have been having which was good because I ended up moving half the rock to get this guy out.
Has anyone ever had one of these things in their tank?? Was I right to take it out??
BTW this thing freaked be out!!!!! When I first saw I said that I was never putting my hand in the tank again. 1 pair of latex gloves and 1 pair of dishwashing gloves later I was still squeamish, but got it done.
 
btldreef

btldreef

Moderator
You got it out, right? Did it have black or black tipped claws? That's usually the first sign that it's a bad crab. Xanthid crabs are a common hitchhiking crab, just as the Gorilla crab is. Xanthids usually have a very, very hard shell and tend to close themselves up and look like a little rectangular stone.
Be glad it is out. Xanthids are known killers. When small they'll eat your inverts, as they grow bigger, they will go after fish.
 
sweatervest13

sweatervest13

Active Member
Quote:
Originally Posted by BTLDreef http:///forum/thread/385174/xanthid-crab-no-pics-sorry#post_3377008
You got it out, right? Did it have black or black tipped claws? That's usually the first sign that it's a bad crab. Xanthid crabs are a common hitchhiking crab, just as the Gorilla crab is. Xanthids usually have a very, very hard shell and tend to close themselves up and look like a little rectangular stone.
Be glad it is out. Xanthids are known killers. When small they'll eat your inverts, as they grow bigger, they will go after fish.
SUPER glad his is out!!! His claws were all black, when he closed up while I was trying to catch him it looked like a rectangular stone. I was wondering why every two weeks or so I would have a half eating hermit crab in the sand and an extra shell laying around. It must have been him. Can't beleive that I had never seen it before, the missing hermit crabs have been happening for about 6 months now, maybe he was on the live rock I frist got when I set up the tank. I think that my new 125g will have mostly base rock. I don't like weird/ bad hitchhickers.
 
btldreef

btldreef

Moderator
You can use mostly base or macro rock to cut down on hitchhikers, but if you still want to use the LR from your tank now, you can. If you want to make sure there are no hitchhikers in your live rock do this:
Fill a bucket with high salinity water. Make it 1.030 or higher. Place an eggcrate on the bottom of the bucket (sometimes it helps to have the eggcrate about an inch or two off the bottom). Place the rock in the bucket. The high salinity will almost always make hitchhikers leave in search of lower salinity. Bear in mind that you'll have bristleworms, etc that will also come off the rock, but at least you'll still have some coralline to help spread to the base rock.
 
sweatervest13

sweatervest13

Active Member
Quote:
Originally Posted by BTLDreef http:///forum/thread/385174/xanthid-crab-no-pics-sorry#post_3377013
You can use mostly base or macro rock to cut down on hitchhikers, but if you still want to use the LR from your tank now, you can. If you want to make sure there are no hitchhikers in your live rock do this:
Fill a bucket with high salinity water. Make it 1.030 or higher. Place an eggcrate on the bottom of the bucket (sometimes it helps to have the eggcrate about an inch or two off the bottom). Place the rock in the bucket. The high salinity will almost always make hitchhikers leave in search of lower salinity. Bear in mind that you'll have bristleworms, etc that will also come off the rock, but at least you'll still have some coralline to help spread to the base rock.
Yup, I will use mostly base or macro rock for the new build. I like the idea of using high salinity water to drive the hitchhikers out. But don't I want to keep some of the good ones like bristleworms???
 
slice

slice

Active Member
Quote:
Originally Posted by BTLDreef http:///forum/thread/385174/xanthid-crab-no-pics-sorry#post_3377013
You can use mostly base or macro rock to cut down on hitchhikers, but if you still want to use the LR from your tank now, you can. If you want to make sure there are no hitchhikers in your live rock do this:
Fill a bucket with high salinity water. Make it 1.030 or higher. Place an eggcrate on the bottom of the bucket (sometimes it helps to have the eggcrate about an inch or two off the bottom). Place the rock in the bucket. The high salinity will almost always make hitchhikers leave in search of lower salinity. Bear in mind that you'll have bristleworms, etc that will also come off the rock, but at least you'll still have some coralline to help spread to the base rock.
If the above is not in Tips and Techniques yet, it should be. Maybe a part of sticky.
 
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