Please Help ID Crab

micahs

micahs

New member
Anybody know what kind of crab this is? He is about 1 1/2 inches wide.

I have had this hitch hiker in my tank for over a year and a half since I set up my tank. He seams to spend all his time in a little cave and I have not seen him hurt coral or any fish. He only becomes a little bit of a nuisance when he is about ready to malt. When he goes around trying to find shells and things to block the openings to his cave, that's what he is doing in the pictures.

Have become a little worried about him because I have recently have had a couple little fish disappear. A Sixline Wrasse that looked and acted healthy disappeared over night after about a week being in the tank. And a McCosker's Flasher Wrasse disappeared the first night but could have been from stress. Never saw either body. I also have other small Gobies that are doing great so I don't know if the crab is the culprit.

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Thanks
 
I'm sorry, but he could certainly be the culprit. He is 100% from the Xanthidae family, and I am almost certain he is Actaeodes tomentosus. Regardless, he would certainly be considered a nuisance crab. Any crab with black tips is almost certainly a flesh eater, and the pointed tips indicates flesh eater and rock crusher.

My suggestion, if you like the little guy (and who doesn't love crabs?!) would be to just feed him as consistently as you would anything else. Crabs are very content when full. They become lazy and will stay where they are because of their good fortune.

Good luck to you.....
 
Recent studies have shown that a lot of these small xanthid crabs are primarily algal grazers, scavengers, & predators on smaller animals like worms. That's not to say that one won't be destructive or go after a sick/dead fish or coral, just that they may not be as evil as most people assume. Since this one has been around for 1.5 years without obvious harm it seems fairly benign. As Kyle said, supplemental feeding would help keep it that way.
 
LeslieH said:
Recent studies have shown that a lot of these small xanthid crabs are primarily algal grazers, scavengers, & predators on smaller animals like worms. That's not to say that one won't be destructive or go after a sick/dead fish or coral, just that they may not be as evil as most people assume. Since this one has been around for 1.5 years without obvious harm it seems fairly benign. As Kyle said, supplemental feeding would help keep it that way.
Click to expand...

This is true...and I am not sure why I didn't mention it. I have been studying crabs for 10+ years, and figuered you knew what I knew!! Duh!

(I swear this is what I had been thinking when I typed......) I also believe that the "danger" these crabs pose is very limited....and usually only due to lack of feeding (naturally, hand-fed or otherwise). He should be fine.

What I had meant by a possible culprit is that crabs are naturally skitish, with fast reflexes...and something caught in its claws out of offense or defense always has the potential to become a meal. So, a careless fish could have "created" the problem...

You should be good. On a side note, if you feed the crab more, he will come out more and therefore will be fun to watch. Crabs are the best in my opinion!
 
Really appreciate all the helpful info guys.

Yesterday he finally unblocked his cave after being closed in their for about 3 weeks malting. Now he is out of his cave digging around in the sand under my rocks probably trying to find a bigger home. I was wondering before he malts maybe he might become more aggressive looking for food and might drag a sleeping fish in his hole so he can have sustenance while he is trapped in there malting.

I do like him, but if I get a chance I will probably try to get him out of their, just to be on the safe side. That will be hard though because he is so quick when he wants to be and dose not stray far from his hiding places.

Just worried he might just keep getting bigger he has already doubled in size. Anybody know how big a crab like that can get?

Thanks, btw Konolua I really love your volcano tank! Checked out your whole thread and thought is was very creative.
 
micahs said:
Really appreciate all the helpful info guys.

Yesterday he finally unblocked his cave after being closed in their for about 3 weeks malting. Now he is out of his cave digging around in the sand under my rocks probably trying to find a bigger home. I was wondering before he malts maybe he might become more aggressive looking for food and might drag a sleeping fish in his hole so he can have sustenance while he is trapped in there malting.

I do like him, but if I get a chance I will probably try to get him out of their, just to be on the safe side. That will be hard though because he is so quick when he wants to be and dose not stray far from his hiding places.

Just worried he might just keep getting bigger he has already doubled in size. Anybody know how big a crab like that can get?

Thanks, btw Konolua I really love your volcano tank! Checked out your whole thread and thought is was very creative.
Click to expand...

Thanks! I appreciate that!

He probably would not get much bigger than a golf ball (flattened out a bit of course), but you can toss him in your sump. They don't require elaborate space like a fish or something would. Plus, he can regulate the sump area too....

When they molt, they tend to go in hiding, but won't eat for about a week. Then, after the molt, they will absorb a ton of nutrients and water to make himself bigger, then begins the hardening process. He would be hungry AFTER the molt if anything.

In truth, you will probably be just fine no matter how you decide to proceed....
 
my friend has had one of these for 4 years, and i had one for 2 years. neither harmed anything except moving stuff around and they did a good job cleaning. my friends is now around 3-4inches wide
 
Well, it looks like a Giant Enemy Crab to me. You should be able to defeat it if you flip it over on it's back and deal massive damage to its weak point.
 
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