Emerald Crab = Serial Killer?

[fishhooked]

In an effort to increase my cleanup crew I added a few snails and an emerald crab. Now about 2 weeks later I have one snail and one scarlet hermit left. 6 turbos and 4 blue leg hermits have vanished from their shells along with any calurpa in the tank (hair algae is still untouched).
Has anyone else had problems with emerald crabs, I thought that these guys were supposed to be reasonably friendly.

 

[dazed1]

I added an emerald this sunday, and all I can see it do is eat hair algae !! It eat's like its not eaten for year's
Probably you have a "naughty" crab ?

 

[tyr-sog]

I'll tell you who the killers are in my tank. Damn little blue legged crabs. Vicious little suckers and there only in a 1/4 inch shells yet seem to beable to murder the much larger(1 1/2inch shells) scarlet hermits. 3 scarlet shells are now homes to blue leggers. Not to mention the snails they tourment.
My emerald is pretty relaxed, just grazes all day.

 

[leboeuf]

I believe it is based on size. I have 6 in my tank. The first one I bought by itself when I finished my cycle. It has been in the tank for almost three months. It has tripled in size since I purchased him. I have personally seen him catch my horseshoe crab out of the water current and turn him upside down and rip out the flesh. I feed the tangs seaweed sheets every couple of days. I suspend the sheets in the middle of the water column so only the tangs have access. Apparently the sheet drifted down and close to a large rock. To my dismay, the large emerald came running out of the dark, jumped out into the open water and grabbed the sheet and fishing line I use to suspend it. He pulled it down to the sand bed and took off to the caves with it. However, he had latched on to the line as well. I put enough tension on the line to pull out a bass, but he never let go. He eventually snipped through the line and it came free.....
Moral of the story, when they get big they troublesome....
JMO

 

[wolffam]

I have 4 emeralds that take care of the bubble algae and some hair algae. I have never seen them go after anything else.

 

[koiman6]

I have had my emerald crab for about two weeks and he has already molted and his carapace is about the size of a 50 cent piece.... these stories are beggining to worry me...

 

[ivanfj]

O man. You guys are lucky that you all see your emerald crab(s) coming out. I haven't seen mine since the first day I added him to my tank.

 

[tired_boy_mike]

I have about 10 emerald crabs in my 100 gallon tank. All of them are about the size of pennies, except for one which is huge ( about the size of a half dollars). I hardly ever see them, but I think they are doing their job. I have zero hair/bubble algae in my tank.
I do have a few empty scarlet hermit crab shells and turbo snail shells. I have no idea what caused their deaths.