Hi everybody!

I have installed my first pond this spring. It's very small (110 gallons) because I didn't want to start with something big and find that I don't enjoy it. I have saved some pretty "feeder" goldfish from the local store after getting the water prepared and such. Here in southern colorado and at nearly 8000 ft in elevation, our spring and fall seasons get really cold at night, down to about 20 degrees. It's very typical for our outdoor ambient temperatures to swing 50 degrees or more from night to day. It's not a very deep pond at 18", and I have small and medium river rock at the bottom. My fish hang out down in the rocks at night and morning. I checked the temperature with a calibrated thermometer this morning and have about 45 degrees water temp. I know that the temperature climbs during the day and that the fish become really active.

My questions are:

Is this type of temperature swing on a daily basis harmful for my fish? Should I consider some type of heater to keep the temperature somewhat the same once spring comes around?

I'm not a pond person, but I have to believe that the wild temperature swings you're mentioning have to be stressful to your fish. Personally, if it was my pond...I'd get a heater.

You should definitely heat your pond. Those kind of rapid temperature fluctuations can definitely be stressful to your fish. Set the heater to the warmest the temp will be in the day and that way, when the pond warms up the heater will shut off, and at ngiht it will click back on. I have a tiny patio pond with a heater in it because our early spring nights would also get very cold.

When you add the heater, very gradually raise the temperature a degree or two per day. Any more than that and you can cause problems too.

Finally, make sure the heater does not come in direct contact with your pond or pond liner as it could melt the plastic. I have mine suction-cupped to a small sheet of plexiglas.

Thanks alot for the answers! Do any of you have a suggestion for a good outdoor pond heater? All I can find is de-icers. I've thought about putting the heater in the external filter as well. Is this a good idea you think?

Okay, this pond heater idea is a good one but it's EXPENSIVE. Unless you have the money to do this I would suggest you bring your fish in when your temps are cold and then in spring get the pond going, in late spring kick the fish out of the inside area and put them out. In the fall bring them in again and drain the pond.

I live in Idaho and our temps fluctuate as well. I keep my fish outside all year round, my pond is 4,000 gallons almost 5 foot deep. In climates like ours your need depth. If you had a deeper pond you could put in a recirculating pump, which means just put your pump in the bottom of the pond with a hose on it and let the water circulate around WITHOUT leaving the pond area, no water falls. Waterfalls and spray bars also cause cooling in your pond. You just need water movement during the cooler times of year if your going to have your fish in the pond.

I hope this has helped some.

Scott