It is a common myth that you can’t leave your pond fish outside once the cold sets in. Actually, fish do just fine during winter. That said, Deck and Patio’s Outdoor Living Expert, Bill Renter, does caution to be alert. When ice covers the pond, the fish might not be getting enough oxygen.
This can be remedied as long as you give them:
- two feet of water to swim in,
- oxygenate the water,
- and keep a hole in the ice with a heater, bubbler and an aerator. This allows the naturally produced gasses to escape from under the ice.
If the above efforts fail to keep it from freezing, Aquascapes Inc. designs manager, Gary Gronwick suggests using a pond de-icer. “This will keep a little hole in the ice so gases can escape,” he says. “While some recommend boiling water to create an opening in frozen-over ponds, that should be discouraged. It will only ice up again quickly.“
Gronwick also says to avoid chopping or sawing the ice to open a hole. The noise and vibrations will stress out the hibernating fish to a point they could die.
That done, Mother Nature will do the rest. The fish will spend the entire winter hibernating at the bottom of the pond, or in a cave designed for this, and then will slowly wake up as the water warms in the spring. The fish do not need to eat during this time and, in fact, shouldn’t be fed at all.