Question
We had two black moors and several fancy fantail fish that had their tail fins snipped off at the body, their side fins basically taken down to the body, scales somewhat removed, and in essence appear that they will not live another minute. To date several of our fish have died after what appear like being attacked. We always have two ducks, a male and female, who enjoy the pond in the Spring, but I am fearful they are attacking our fish. Would they do this? If not, what could do such extensive harm to the fish? We haven't seen any herons in the area. We do have some neighborhood cats, but we always had cats in the area with nothing like this occurring. What can we do to prevent these attacks? The ducks have been there in the past and we never had anything like this happen. To date 5 fish have been attacked - several have died after appearing like they went through a meat grinder.  Thank you

Answer
I'm very sorry about your fish.  Yes, I've had reports from people that ducks do eat fish.  If they are unable to swallow them hole, they could be shredding off their fins.  Other predators might also be to blame.  Raccoons are notorious for damaging goldfish.  Herons will either swallow the fish whole, put a hole in them, or dump them on the ground if they can't swallow them.  They shouldn't mutilate them in the way that other animals will.  Cats may do damage similar to raccoons but they're not very good fishermen.

Have you watched the ducks and seen if they appeared to go after the fish?  What species of ducks?  If it's the ducks, you'd have to net the pond to keep them off to help the fish.  Nets will also keep out most predators except snakes.  Adding smaller fish like rosy red minnows to provide food for them or whatever predator is at fault may help.  I wish there were an easy answer.

http://www.fishpondinfo.com/pmamm.htm

Good luck!