emerald crabs, good or bad?

[bigluke]

ive read emerald crabs could be a threat to small fish, how small is small? the smallest fish id have in my tank would be a firefish. would turbo snails or feather dusters be in danger from a emerald crab?

 

[robbinson]

My understanding is that the emeral crab (Mitrex) is a reef safe crab and that is consistent with my personal experience (I have about 1/2 dozen in my 120g reef). They are great at eating bubble and hair algae (and look very interesting too).

 

[2poor2reef]

This issue with these crabs is that they will pick at polyps and sps tissue, particularly wjen they get larger. I have never heard of one that could catch a fish. I've also never seen them go after snails and ornamental shrimp and such. They will posture with outstretched claws when they feel threatened. They even do that to me when I approach. But I doubt they are trying to eat me. They are good algae eaters and they will eat valonia, which is why I keep them. But they have damaged some of my sps from time to time so I prefer to keep them in a soft polyp tank until I need them.

 

[Enkidu]

I saw one at a LFS that was chewing on a large turbo snail. The crabs body was about an inch and a half across I think, and I don't know if the snail was already dead when it started eating it, but I've started removing my emeralds when they get of substantial size.

 

[esmithiii]

My experience with them has been good. They will eat anything that dies, however which sometimes leads people to belive that they are not reef safe.

Ernie

 

[Jacqui]

They are like MacDonalds and Disney...great cleaner uppers. Mine don't bother anything that is living. I have 5 in a 105 gallon tank. Keep it squeaky clean. They are fun to watch. One of mine is carrying eggs....guess I'll be a grandmother soon.
My gues is that the snail was dead and the crab was doing a good job cleaning up.

 

[jhaag]

I've had 2 of them in my 55 gal with some cleaner shrimp and a firefish for over a year without any issues. I don't have any SPS in there so I couldn't comment on that, but they have never bothered my other corals.

 

[fishnbarefoot]

I've got 7 in my 180.

 

[dobish]

I've had good experiences with emerald crabs and have kept them with SPS, LPS, and softies. They munch on hair algae, have cleared up the valonia, and do a good job on cleanup.

 

[steve F]

Hi Everyone,

In my experience, Emerald crabs are a great addition to your tanks. I had around 7 or 8 in my 150g reef.

Steve