Royal Gramma Belly Missing

[jjonesrjc]

So I was feeding my tank this morning and my royal gramma came floating out of his hiding spot missing his middle section. The only person that was near his hole was my monster emerald crab his body without claws is 1 1/2" when he floated back down the crab proceeded to grab him and go to town right in the spot that was eaten. I have had my tank set up for over 9 months and had to remove one mantis shrimp but it was a smasher and the only casualties from him were snails and hermits not fish. The gramma has been happy and healthy in my tank for about 2 months now no previous signs of disease and my water parameters are on point. The weird thing is I have livestock that is much slower than the gramma so I don't know what would have picked him off in my tank. Inhabitants of my 60g cube are 1 Banggai Cardinal, 1 Longnose hawkfish, 2 false percs, 2 firefish, 1 green spot mandarin 1 cherub angel and 1 pinkbar goby and his tiger pistol shrimp. I also have about 6 peppermint shrimp, 1 cleaner shrimp and about 5 emerald crabs (one being massive and very aggressive) Any ideas as to what could have attacked him and not completely eaten him. I mean if it was another mantis in my tank I don't think it would have let its meal go. Is there a possibility it is my massive emerald crab thats just not getting enough to eat I have seen him try and grab my mandarin and my goby but both scoot away before he can get a hold of them.

 

[speer]

The fish might have died from natural causes and then your emerald proceeded to eat away at the fish's midsection.

 

[Flippers4pups]

Emerald's have been known fish killers. I learned long ago about their tendencies to turn on sleeping fish at night. You should remove them to avoid anymore losses.

 

[jjonesrjc]

Yeh I was thinking it had to have been the large one as the others are only about the size of a nickel each but this behemoth has claws large enough to wrap around my pinky. The reason I did not believe natural causes would have killed it was that it was active eating late last night before lights out and hasn't shown any potential signs of illness plus it was a juvenile gramma.

 

[billdogg]

I have one that I banished to the return section of my sump several years ago. I just have to remember it's in there when I stick my hand in. Turns out they like people to!

 

[Khemul]

That's the tricky thing with crabs/hermits/lobsters in general.

Very opportunistic. They tend to be great scavengers. If something dies, they will be on it and eating it very quickly. They can be good hunters too, if they can get a hold of their food. It all comes down to how much work they can and/or are willing to do to get that fish.

The problem always comes in figuring out which action the crab was doing. If it was scavenging then it was doing its job. If it was hunting then it is a danger to the whole tank. Personally I'd say if you aren't very attached to the crab and are pretty sure the fish was healthy, then remove the crab.

 

[jjonesrjc]

Yeh not attached to them at all I much prefer my pistol and cleaner shrimp to the crabs as inverts in my DT. I'll grab him out tonight. If any other fish go I don't know what I'm dealing with another mantis I haven't seen or possibly a hitchhiker pistol?

 

[jjonesrjc]

Ok confirmed it was the emerald crab. When I got home I went to start taking the crabs out and low and behold there is the monster standing over the hole of my cherub angel which was frantically trying to get out but could not as the crab was larger than him I pulled him quickly and threw him in the fuge. Thanks for the help y'all.