detachable fins

[farmerbob]

So, in our 30 gallon tank, we used to have 2 percula clowns, a royal gramma, a high-fin goby, and a coral banded shrimp. A recent trend has developed in our tank where whole chucks of fin suddenly disappear. It's not gradual, just all of a sudden we have a gimp fish. This seems to happen literally overnight.
This has happened to the smaller percula and our royal gramma, and both died because of it. When asking the local "experts" (haha) I have yet to get two similar responses. Local theories to the problem include:
1) Cuts on sharp pieces of rock
2) Coral Banded Shrimp (my theory as well)
3) Goby
4) Tank rot
5) Aliens
My theory is it's the shrimp, because it happens suddenly, and the wounds are always straight, almost as if the fins were cut with scissors. They don't look like bites of any kind, and our Goby is only an inch or so, the wounds are bigger than his whole head.
Please help!!

 

[farmerbob]

anyone know? or have any opinions?

 

[yae4volcom]

I would try removing the CBS and see if the problem continues. They are known to be killers...

 

[zibnata]

I had a mean CBS that would attack cleaner shrimp and would try to grab fish . It probably attacks when the fish are asleep.Mine would only be visible when the lights were out so I assume they are on the prowl when the fish are sleeping.In a 30 gallon its probably hard to hide from the CBS. I would remove it and get a Cleaner shrimp instead.

 

[zibnata]

I had a mean CBS that would attack cleaner shrimp and would try to grab fish . It probably attacks when the fish are asleep.Mine would only be visible when the lights were out so I assume they are on the prowl when the fish are sleeping.In a 30 gallon its probably hard to hide from the CBS. I would remove it and get a Cleaner shrimp instead.

 

[1journeyman]

Another vote for the shrimp... either that or you have a hidden "guest" of some sort in your tank taking bites out of them.