Keep your pond fish healthy in winter

What happens to pond fish in winter? And what does a responsible pond owner need to do to take care of these fish? You’ve got questions … and Good Earth Water Gardens has answers.

The basics

If your koi pond is at least two feet deep, the distance between the earth and the surface of the water won’t allow the water to freeze any deeper than eight inches. So, there will always be at least 16 inches for the fish to hang out.

To keep this aquatic lounge open for business, you do need to keep a hole in the ice. This will help gases like oxygen and ammonia escape and keep your fish comfortable. You can maintain this hole manually or with a pond heater/deicer. Running your waterfalls, adding a bubbler, or churning the surface water with a pump can also help.

Do fish hibernate?

Sort of. Goldfish and koi aren’t big fans of winter. They don’t thrive in it – they survive it. During cold weather, a fish’s immune system doesn’t really function. The fish go into a state of torpor. This is like hibernation, but shorter. Metabolic processes slow down and the fish save energy. This is also why fish don’t eat during cold periods.

Fish pond deep dive

We checked with our friends at Aquascape and they shared more detailed information about goldfish, koi, and their cold-weather habits. Here are some things to keep in mind:

  • Winter slows down fish – but not parasites and pathogens. Some of these bugs are actually more active in the cold. Fluke, ich, tichodina, and costia can be hard at work trying to infect your fish. So remember that a hibernation-like state doesn’t mean your fish are insulated from infection.
  • Temperature swings within the pond are stressful to fish. Variations of more than 20 degrees Fahrenheit can make fish more vulnerable to infection.
  • When you’re thinking about temperature swings, consider your waterfall. It can dissipate heat or pick it up from the pond water. Some folks run their waterfalls during the day to gain heat, then turn them off at night to avoid the cooling. This works if you have another form of submerged pond circulation for aeration.

The final word on fish

It doesn’t matter what kind of fish you have – no fish can be frozen solid in ice and survive. It might look like your pond is frozen through, but if it’s at least two feet deep, it isn’t. Your fish friends are still hanging out in their aquatic clubhouse, trying to keep warm.

At Good Earth Water Gardens, we love our aquatic amigos. If you have questions about koi or how to best prep your pond for winter, we can help. Give us a call today at 913-749-8090 or contact us online.