Emerald Crabs

[Deitta]

I have been having some bubble algae issues, was thinking my next guest in my 6 gal would be an emerald crab. But need more info!
1) Once the bubble algae is gone, what is the prefered food?
2) Do they attack anything else? Or anyone else?
3) Are they known to attack peppermint shrimp? Which is the next planned guest.
4) No other guests were planned due to size... but could I?

 

[AndyH5512]

I have 4 emeralds in my 120. They will eat anything the fish let go to the floor. They keep the substrate nice and clean. Mine have been good with my fish, however I have heard some folks on here say that a hungry emerald could grab a sleeping fish. Im not sure about the peppermint, never had that situation.

 

[ZoozFishMaster]

Emerald crabs are opportunistic creatures, meaning they will adapt their diet to the food available. They can be great at controlling nuisance algae (if enough is present). They will also accept meaty foods (shrimp, krill, squid, etc). However if not enough food is present, they may give your smaller fish, invertebrates, and possibly corals a try.

 

[afilter]

Great cleaners. I have two in my 75G. They readily accept any food that hits the bottom in addition to scavenging.

 

[Guest]

I had two emeralds in a 55 reef. They never seemed to bother any of the fish or shrimp, but they loved the four differant leathers I had. After watching three pieces of coral get torn apart I decided that it would be easier and cheaper to remove them than to keep feeding them coral from the pet store. Oh yeah and that was with trying to keep those guys feed with differant types of crab food. Just didn't work.

 

[lando]

I have two emeralds in my 12gal nano. Just FYI...I have never found an emerald that will eat bubble algae.

 

[jaiden]

I'm no expert at all, but I've seen pics of emeralds where they have two small claws, and others with one bigger claw. I have also heard reports that the big claw variety are more dangerous to fish. I have no firsthand experience with the big claw kind, but they look pretty much the same otherwise. I don't know if it's a different species or maybe it's a gender difference?

 

[Scottm]

I would bet its a different species. Most species of invertibrates are very hard to tell apart without examination of internal organs or alot of information about very specific things you can ussually get their genus just by looking though and thats why they call them Mithrax crabs.

 

[Snoopybdb]

i've had 3 different emerald crabs he first 2 would not mess with the bubble algae, but the 3rd one i have now has been seen eating it.
**just a funny side note**
i don't know if this has ever happened to anyone else but i went on vacation for a week and my mom was taking care of my tank while i was gone. one day she called me and said i think your crab is dead it's in pieces on the bottom of the tank. after talking to her i thought i bet it shed. when i got home sure enough the crab had shed but the funny part is that it had more than doubled in size! I thought i bet it looked like the hulk breaking out of it's tiny shell! LoL