Emerald Crabs

[paulthomas]

I've got six in QT, right now, and plan on putting them in my 240 when ready. My understanding was that they're great for controlling GHA, bubble algae and other various algae. I researched a bit more on them, today, and read that in not-so-rare occasions, they're known to eat fish and corals if not fed enough.

Does anyone have these problems with them?

Thanks,
Paul

 

[amutti]

I can't imagine one eating a fish?? I have a bunch in various tanks and never saw anything like that. I have seen them fight one another (to the death). I also haven't had the experience of them eating coral, but that seems more likely. All crabs are opportunistic feeders.

As proof they eat bubble algae, here is a video I took 6 months ago or so:
http://www.youtube.com/watch?v=0rvuWYPC2to

 

[paulthomas]

Cool video.

My emeralds aren't quite that green in color. Might that have something to do with a deficiency in their diet or just their size? They're all pretty small, like dime to nickel sized carapaces.

Thanks,
Paul

 

[graysmurf]

Very cool video, do they pop the bubble algea or eat them whole?

 

[Reefer577]

I've heard the fish eating reputation and didn't use emerald crabs for a long time because of this. A year ago or so I finally got sick of the bubble algae and got some. Mine have always been model citizens, even some that grew too 2+ inches. I've kept them with some fish that were smaller than them with no problems. Maybe if they run out of algae and you never feed your tank, then they might attack your fish?

 

[smokey377]

Mine has moved into a sps acro, has been their for a week reminds me or a arco crab is this something to worry about sps seems healthy?

 

[thebkramer]

Never had a problem with my emeralds either.
They may irritate corals when they are scraping off algae to eat, but thats about it IME.
They will be the first among CUC to jump on a fish that has died though!
You'd be surprised how fast they will tear apart that dead fish too! lol

 

[Guygettnby]

never had an emerald crab bother a fish ever, unless the fish was dying or dead. i think the only real crab i had that bothered fish that was supposed to be reef safe was a sally light foot. i also never had an emerald mess with my corals unless they were cleaning algea off of them or unless the coral was dying or dead. but you gotta remember that any crab or even shrimpfor that matter is an oppertunist feeder. but they also do there jobs of cleaning up.

 

[sparrow7679]

I have one in my 30g for about 6months. It has never bothered any coral or fish either. Always see him eating algae tho. I think they only get aggressive when they are under feed and are full grown.

 

[sin142]

That might explain where some of my star polyp, mushrooms and zoos went. Never actually witness them eating my corals but something Is getting at them because there's no trace of them. Cool little guys to watch when there out tho.