Number of Mithrax Crabs

[Snoopdog]

I seem to remember years ago that having more than one emerald crab was bad, that they would fight until one died. Is there truth to that? I have a 69 gallon tank with a good bit of live rock. Is more than one emerald crab an issue?

 

[New&no clue]

I have two in 75 gallon and then seem to get along fine.

 

[Snoopdog]

I have two in 75 gallon and then seem to get along fine.

Male or females or mixed?

 

[New&no clue]

Male or females or mixed?

I have no idea, one is big one is small.

 

[Snoopdog]

I have no idea, one is big one is small.

I think the males have a large claw and small claw, but now reading that may be completely incorrect.

 

[Coralsdaily]

personally I think it's a myth. I have seen tanks with multiple of them. Also, even though this isn't long term, but LFS always jam pack a dozen of them in a tiny space and I don't see them murder each other there.

 

[Snoopdog]

personally I think it's a myth. I have seen tanks with multiple of them. Also, even though this isn't long term, but LFS always jam pack a dozen of them in a tiny space and I don't see them murder each other there.

I did actually witness then rip each other's arms off back when i had a Biocube with two of them. They were always bowing up to each other and locking arms, then one just ripped the other one's arms off.

 

[Tired]

My suggestion for how many to keep is generally "zero". Once they get big, they can be a threat to small fish. Best kept only in tanks with big fish.

 

[xxkenny90xx]

My suggestion for how many to keep is generally "zero". Once they get big, they can be a threat to small fish. Best kept only in tanks with big fish.

0 sounds about right. Crabs are not to be trusted. If you must have crabs go with porcelain crabs (they're not technically true crabs)

 

[Coralsdaily]

despite sharing that stores keeping a bunch in a small space, I personally have never had them for the exact reason Tired & Kenny both shared. I don't want to risk them ripping into my other inverts, and to potentially hunt down my sleeping fish. on that note- also say no to sally lightfoot.

 

[Tired]

Oh, yeah, porcelain "crabs" are a good alternative. They don't eat algae, but they're neat. Green ones can be kept in small groups, white ones (porcelain anemone crabs) should have an anemone of some form to host, but are very pretty and fun to watch. Their claws are mostly for display, they primarily filter-feed (though you can give them larger chunks of food to keep them healthy), and they lack the ability or the gumption to go after tankmates.

Other animals to avoid are, yes, Sally lightfoots, arrow crabs, and coral banded shrimp. Little ones may work (the smaller species of CBS are generally fine), but once they grow you start to have problems. Things with claws tend to use those claws.

 

[Coralsdaily]

Oh, yeah, porcelain "crabs" are a good alternative. They don't eat algae, but they're neat. Green ones can be kept in small groups, white ones (porcelain anemone crabs) should have an anemone of some form to host, but are very pretty and fun to watch. Their claws are mostly for display, they primarily filter-feed (though you can give them larger chunks of food to keep them healthy), and they lack the ability or the gumption to go after tankmates.

Other animals to avoid are, yes, Sally lightfoots, arrow crabs, and coral banded shrimp. Little ones may work (the smaller species of CBS are generally fine), but once they grow you start to have problems. Things with claws tend to use those claws.

My favorite crab, they are so sassy too they try nip fishes getting to close to their anemone