I have recently suffered some deaths due to mouth rot and finally thought I'd sorted out my pond. Then I found a small goldie with a wedge-shaped "bite" taken out of his head. Funnily enough he still seems happy enough swimming around with one eye. Still, I thought Heron?

Sadly, a few days ago I found a dead goldie with a suspicious looking wound in its side. I had a good look at it and it definitely looked like something had had a go at it (rather than disease) but it was slightly larger than I would expect from a beak attack (and not very deep).

Then today I have just buried one of my very first fish I bought, a lovely shuby, with a very large chunk taken out of its rear end. I've attached a photo as I really am not sure what could have caused it. It does not look to me like a bird attack and as it is on the underside of the fish that would tend to suggest it was attacked from underneath... There was some plant disturbance but I can't rule out the wind for that. We have a koi around 10 inches which is relatively large compared to the others. Have koi ever been known to attack other fish? Even if they have he seems very docile and doesnÂt ever go after the others when IÂm around. Plus we have a load of babies at the moment so I would have thought heÂd just eat them if he got peckish.

I would be very grateful if anyone could help me find out what's going on here so I can prevent the loss of any more of my little friends. I've thought of heron deterrents and netting, although I don't really want to cover the pond all the time as there's not a lot of point in having one if you can't see it.

Thanks for any help!

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