Mithrax ??

[SirFragalot]

I was finally able to get a pic of the crab that decided to push my hammer coral out of the rock to make a home. (I put my hammer coral here first) I have actually seen two of these types of crabs in my tank. One is slightly smaller than the other. This one being a little over an inch wide in the body. I think that they are a mithrax of some sort? In the last pic, you can see the live rock rubble that it has dragged into that cave to make a roof. It's amazing how much weight those guys can pull around.

 

[mikem]

Yes, you wouldn't believe the size of the rock that crabs can move.
You can tell what kind of crab it is by the claws. Matrix crabs have rounded pincher's with no point on the end.

 

[SirFragalot]

Think it would be safe to leave him alone and let him have his cave? Or should I get him out? The only negative thing that I have seen it do is when I first got my hammer coral frag, I placed the base of it into that cave and the next morning, I found the hammer laying on the substrate.

 

[RU_Coral_Guy]

hmm... can't get a good look at your crab there... however, I can say that you're hammer coral frag may need to find a new home if this guy is stubborn... or you can just appoxy it into place.

 

[SirFragalot]

hmm... can't get a good look at your crab there... however, I can say that you're hammer coral frag may need to find a new home if this guy is stubborn... or you can just appoxy it into place.

After finding that he pushed it out, I just plunged it into the substrate right in front of that rock. http://www.njreefers.org/joomla/index.php?option=com_smf&Itemid=26&topic=17862.0
After a few days, I moved it up half way to a different rock for more light.

 

[mikem]

They're good at cleaning rocks and sometimes bubble algae.

 

[SirFragalot]

Do you guys have any more input after my update on todays post about another crab? http://www.njreefers.org/joomla/index.php?option=com_smf&Itemid=26&topic=11225.0

I posted that last year and probably should have done it in this section.

 

[mikem]

Color don't matter too much. It's the piercing pointy claws that make it a predator.

 

[diverrk]

I had a crab in my tank, thought it was a emerald, but he terrorized my tank. Stealing frags, moving rock, it took time but he's out and I'll never add another crab to my tank, to me it's not worth the hassle.

 

[SirFragalot]

Ok, I have made the decision to get rid of the 3 crabs (that I know of). I have heard of many different ways to go about this but what is the easiest route to take for this action without ripping apart the aquascaping? I'm also willing to play the "if you can catch them, you can have them" game if there are any takers.

 

[mnat]

Do you ever see them during the day? Mine used to come out at feeding time and that is when I grabbed the buggers. Also, if you find where they are hiding then you only need to pull out that rock.

If you don't see them during the day, turn the tank lights off and just wait. I would recommend drinking through this, but that is just me. People have also tried various DIY crab traps which I am sure you can search for.

 

[RU_Coral_Guy]

They're good at cleaning rocks and sometimes bubble algae.

If they are emeralds, then yea... the one's i have had were very successful at keeping my bubble algae (valonia spp.?) in control. They were never a bother to anything in my tanks besides the valonia though.
As far as the pics of the crab you posted last year... they are nasty little hitchhiker that grow fast and will kill all your snails and hermits quick and leave a graveyard of empty shells outside its lair!