Question about Emerald Crabs

[monkeysee1]

Hi again everyone!!
I HAD two Emerald Crabs in my tank, for about five or six months now, and thought everything was great.
That is, until this afternoon I when I came home and saw one of my Emerald Crabs eating the other!
So now I'm down to one.
Question is, I don't know if the one that was being eaten was KILLED by the other or if it was already dead and the other took advantage.
Are they THAT terrirtorial?? If you have more than one in a tank will they fight to the death - or is this just a fluke thing where maybe the dead one was just sick?
I've noticed that night time would be the time they would come out; I would rarely see either of them during the day. And one WAS A LOT more shy and reclusive than the other. Hmmmm.
ANY thoughts, anyone???

 

[heathlindner25]

I would imagine the crab probably just died, and the other one took the advantage.

 

[Reef of Fillory]

I had two emeralds, they hung out together, then they started eating my zoas together, then they went to the sump and ultimately the lfs together... -_-

Never had a problem with aggression from my two

Sent from my Galaxy S8+ using Tapatalk

 

[vikinglord13]

emeralds are cool-looking crabs; however, they are annoying. I've had two die. The first due to starvation, no question about that. I'm not sure if the second one starved or was molting then died during the molting process (if it starved it was stupid as there was GHA everywhere). I am now on my third and as far as I can tell, this one isn't eating the GHA either. I'm about to be done with these.

 

[Ron Reefman]

emeralds are cool-looking crabs; however, they are annoying. I've had two die. The first due to starvation, no question about that. I'm not sure if the second one starved or was molting then died during the molting process (if it starved it was stupid as there was GHA everywhere). I am now on my third and as far as I can tell, this one isn't eating the GHA either. I'm about to be done with these.

Mithrax crabs are not big green hairy algae eaters IMHO. I collect them in the Florida Keys and I find they like to pick at small stuff rather than go after a field of GHA. Some do like bubble algae, but then some don't, I think it's very hit and miss.

To the OP, I think the crab was just taking advantage of the fact that the other crab had died. I've had multiple mithrax crabs in a small container when collecting them in the wild and I can't say I've ever seen them fight.

 

[monkeysee1]

Thanks a heap, Heath, Fillroy, Viking and Ron!
I guess knowing that Emeralds aren't inherently aggressive towards each other while LIVING means I can get a couple more to put in my QT for awhile, then into my DT.
Great info, folks! :wavehand:

 

[saltnewb]

Mithrax crabs are not big green hairy algae eaters IMHO. I collect them in the Florida Keys and I find they like to pick at small stuff rather than go after a field of GHA. Some do like bubble algae, but then some don't, I think it's very hit and miss.

To the OP, I think the crab was just taking advantage of the fact that the other crab had died. I've had multiple mithrax crabs in a small container when collecting them in the wild and I can't say I've ever seen them fight.

i agree mine always seem to wander around picking at little bits of whatever but never touched GHA, a few times I seen it hangin on my corals and thought it was eating them but it must have been a piece of bubble algae or something cuz the corals were never hurt.

 

[slowmoclown]

They did a good job the first week with the GHA but stopped eating after the first week. I also found them eating my zoas...

 

[bcb577]

They did a good job the first week with the GHA but stopped eating after the first week. I also found them eating my zoas...

I stopped getting emeralds due to eating my so as too.

 

[vikinglord13]

Sorry it's been awhile.

They are scavengers more than anything. I've seen multiple crabs sitting in a tank and they didn't care about each other.

 

[Kobin]

My guess is that either one of the crabs died and the other was taking advantage of it or there wasn't enough food to scavenge in the tank. Emerald crabs tend to go for anything if they're starving, but usually behave well if there's enough food in the tank aka algae.

 

[vikinglord13]

My guess is that either one of the crabs died and the other was taking advantage of it or there wasn't enough food to scavenge in the tank. Emerald crabs tend to go for anything if they're starving, but usually behave well if there's enough food in the tank aka algae.

If the particular individual crab eats algae. I've had one die on me with akgae all over the tank