I lost fish this year too but I think it was because I am overstocked..are you overstocked? Sorry no fish expert but my pond has been going for 3 years now and this year I lost fish..never before :(

Sorry about the loss of your fish. Some causes could be an overstocked pond, a pond with debris on the bottom that is rotting and releasing toxic gases, fish that did not have enough body fat and proper nutrition, not having a hole big enough to promote gas exchange,bacterial infections, ect.

Since our fish have to fast over the winter and endure extremes in weather it really is a wonder that so many survive.

my pond is 7 by 16 feet and I have only gold fish .We take them every year put them in a kids plastic round pool in front of a window in the basement with 2 small pumps.never lost any.but I dont know what to do with the goldfish,have to many.Any good ideas?

How deep is your pond, Sigrid, and what zone are you in? Most of us leave the fish in the pond over winter if the pond is about three feet deep. Goldfish (comets) are usually pretty hearty.

Thank you for the information I lost 6 8 year old koi but it was what u said debree on the bottom I have had this pond 8 years lost one or two never this many I did have alot of fish but they were here for 8 years so I drained part of the water refilled never have I cleaned bottom how do yo clean the bottom

I am not an expert because I don't do much myself and I only have comets. However, some people use a shop vac or similar to suck crud off the bottom. Others drain part or most of pond to be able to reach and grab or rake some crud after removing fish to a separate area. I have a stream as well as pond. After removing overgrown plants or whatever, it stirs up the bottom. Part of this suspended crud gets pumped to the stream where it gets caught in the great tangle of stream plant roots and other junk. I often pull some of this crud from the stream. My pond and stream are always clear except after one of these activities.

vansanst, unfortunately, I don't think any of us really understand the direct cause of fish death. I suppose you m.ight be in the best position to give some advice. If you found a specific pond test to be severely out of normal range it might point you or us in the right direction to prevent future death. Or perhaps not. It seems to me that over the years, many of us have done things that others said could cause trouble without in fact creating that trouble. For example, I have disturbed long standing bottom crud; had my pond completely iced over an inch or more for a month; and left a pond completely undisturbed with no circulation for years at a time, all without problems.

Thanks for your response

Different vacuum methods.

Thanks