View Full Version : emerald crabs....

05/20/2007, 06:50 PM
I have an outbreak of bubble algae so the LFS suggested getting a couple of emerald crabs to eat the bubble algae. But...the crabs have not gone for the bubble algae. the $5. crabs are going after my $60. pulsing xenias. Is this normal?. Do emerald crabs eat coral? Did I screw up and put a preditor into my calm reef?.

As always I appreciate all the help


05/20/2007, 06:56 PM
As far as my experience goes it depends on the crabs "personality", I had 4 in my tank and all but one were good. Caught the one at night nipping on my shrooms, gave him away. Haven't had any problems with any of the others, hope this helps.

05/20/2007, 07:46 PM
How did you catch him?. He's paranoid and hides when I approach him?.

05/20/2007, 07:56 PM
one of those mower bleny fish things could help

05/20/2007, 07:59 PM
I have gone through 4 emeralds. Not one ate bubble algea. I have never heard of one going for coral. As mentioned, it is hit or miss.

05/20/2007, 09:42 PM
i put 2 in my 20 for algae control... one ate all my zoo's then hit the salad bar. they might have made some attempts at my kenya trees but never did any damage... never went after my xenia, unless it grew back before i noticed...

between 2 emeralds and an urchin, no more algae , no more zoo's.

05/20/2007, 09:49 PM
My 2 emeralds in my 55 don't bother my zoos or any other of my corals. I don't have any xenia though. My emeralds did eat some zoos once, but this was because the zoos were DOA from some student guy in Ohio selling $10 zoo frags. I tried to salvage them, the crabs senced death and mowed them down. Other than that the are good at eating algae and I don't have any bubble algae.

05/20/2007, 10:47 PM
Actually,there are more than 1 type of emerald crabs.I recently added 2 from a local store solve my bubble algae problem.I have watched them graze on mostly corline and not the bubble.They will grab at it nowand again,but can't pull it off.The stuff is just too tuff.

05/25/2007, 04:20 PM
I have 4 emerald crabs that I bought to control a major algae problem that I was hitting on month 3 of my 75g reef tank. I put the 4 emerald crabs in. Right away, one of them went to a piece of algae infested liverock and went to town. I thought life was good. Soon after, the crabs crawled deep into my live rock and do not come out, day or night, i cannot spot these guys. I have only had success taking a flashlight at night and peering into my 3 huge pieces of live rock. they are near the middle of the stone and apparrently eating well inside. Unfortunately, that has not helped curb the algae on the liverock, or the sand. Believe it or not, my sand star, my pincushion urchin and 25 astrias did a better job.

05/25/2007, 04:36 PM
I have an emerald crab and he ocassionally, pulls a tentacle off of my anemone, when he comes out of hiding that is......

05/25/2007, 04:46 PM
My emerald is a model citizen. So well behaved that he doesn't touch the pulsing xenia or the bubble algae. Now the brown plate algae was a different story! :)