Emerald crab a villain?

[mkwarner77]

Question, Will large emerald crabs, go kill fish? I've had multiple fish vanish in the last month. No apparent signs of illness. All have been eating well and active in the tank. The last was a blue green chromis. He was healthy and active when the lights powered down for the night. I got home from work the next day and there was a large red mark on his right side. He died in less than a half hr after I got home. The emerald in question is over 3" in width and a beautiful dark green. I him and 2 others at the same time about 4 mos ago. there's only 1 other left, it's small, just under 2" and pail green. The only other thing in the tank that could be a culprit is a pistol shrimp, he's just over 3" in length. The lost fish were a lawnmower blennie and a ruby red dragonette, both had been in the tank over month. current population of the tank are, 2 small mocha clowns, a yellow goby, 4 turbos and 3 narsis. 46 gl tank

 

[mkwarner77]

Question, Will large emerald crabs, go kill fish? I've had multiple fish vanish in the last month. No apparent signs of illness. All have been eating well and active in the tank. The last was a blue green chromis. He was healthy and active when the lights powered down for the night. I got home from work the next day and there was a large red mark on his right side. He died in less than a half hr after I got home. The emerald in question is over 3" in width and a beautiful dark green. I him and 2 others at the same time about 4 mos ago. there's only 1 other left, it's small, just under 2" and pail green. The only other thing in the tank that could be a culprit is a pistol shrimp, he's just over 3" in length. The lost fish were a lawnmower blennie and a ruby red dragonette, both had been in the tank over month. current population of the tank are, 2 small mocha clowns, a yellow goby, 4 turbos and 3 narsis. 46 gl tank

Chromis didnt have a mark on him less than 24hrs earlier

 

[mkwarner77]

Chromis didnt have a mark on him less than 24hrs earlier

Suspect

 

[ca1ore]

In the case of the chromis, that looks like uronema. Was it a recent addition? Chromis really should be quarantined as they are quite prone to the uronema parasite and it's something you don't want in your tank. My standard response to these kinds of questions is that while it is always possible that there is some lurking boogeyman in your tank, the much more likely explanation is that the fish died of either disease (chromis) or starvation (blennie, dragonette).

 

[Chuk]

I would say a emerald crab wont get a healthy fish. I've kept them for years and haven't seen them snag a fish out of the water column.
But one time I had one green chromis that was getting beat up by the rest of the school, it was runty/ slow and had ripped fins, bite marks, and all. I found the crab picking the skeleton clean on that one. To be fair I'm not sure if the crab killed it or just had a feast once it was dead.

 

[mkwarner77]

In the case of the chromis, that looks like uronema. Was it a recent addition? Chromis really should be quarantined as they are quite prone to the uronema parasite and it's something you don't want in your tank. My standard response to these kinds of questions is that while it is always possible that there is some lurking boogeyman in your tank, the much more likely explanation is that the fish died of either disease (chromis) or starvation (blennie, dragonette).

He had been in the tank over a month.