Can you supply some more information? Where are you located? How deep is the pond? In ground or above? Does the trickel if water dump dirrectly into the pond or go over a falls? Maybe you can post a photo.

Mike

I'm in zone 5 and while I used a homemade lightbulb heater the first few years, I just run the pump all winter and use a bubbler now.

I live in Massachusetts very cold in winter. There is a small plastic mini pond above the main pond, the water flows through vegetation in there and falls down to the main pond as I said in a trickle.

gdnh, The small upper pond will likely freez near solid and stop the trickle of water. To winter fish in the pond, you need at least 24 inches of water depth and to maintain a hole in the ice to let gass exchange from the pond water.

Please review the other resent post topic, about deicer question.

I think you should bring your fish in. It doesn't sound like your pond can be quickly adapted for winter. Use your pond pump to lower the water in the pond so that you can catch the fish.

How deep is your pond? Is your biofilter in a plastic container or similar as it will freeze and most likely crack. If your pond is more than 2" deep, it is likely your fish will be ok for the winter.