How To Do Winter Koi Pond Maintenance In Colorado

Keep Your Fish And Pond Safe During Colorado Winters With These Maintenance Tips

Winter koi pond maintenance is important for keeping your fish safe and your pond working. It can also help make your spring pond wake-up easier too. Knowing things like should you leave your water running and the best ways to care for your fish can help make your pond experience a great one (and easier).

One of the most important tips: do not feed your fish when it gets too cold (find out the exact temperatures in the article).

Winter Pond Maintenance

Winter Koi Fish Care

It’s Already Winter, What Do I Do?

But What About Our Koi Pond?!

“It’s calling for snow! Wait, what about our koi pond?!”

Pond in Colorado Springs

Carol and Carter love their new koi pond, but they aren’t sure what to do with it during the winter. Here in Colorado, the water will freeze and they’re afraid their fish will become fish-cicles! Carter’s worrying more about the actual pond breaking down than the fish (somebody has to).

Neither of them are about to let winter arrive without preparing their pond for it. Carol rushes over to the computer to see what she can find on winter koi pond maintenance.

Winter Koi Pond Maintenance

Carol first reads about whether or not to turn off the pond.

You can either turn off your koi pond or leave it running. If you keep it running be sure to keep an eye on the waterfall as ice dams can form and send water into your yard. Make sure the pond is always full so the pump doesn’t run without water. For shutting it down, take out the pump to release all the water and store it inside in water.

If you leave it running you’ll see some beautiful ice formations like this form:

Cool partially frozen waterfall

You’ll also want to clean your pond before it freezes over. All the muck and debris sitting in the bottom over winter will smell really bad and make spring pond cleaning di-ffi-cult. 

You can do it yourself or you can use a professional pond maintenance service. 

Carter breathes a sigh of relief knowing that winter koi pond maintenance isn’t too difficult, besides the cleaning part. Now Carol searches what to do with koi fish during the winter.

How To Care For Koi Fish During Winter

Carol has a few questions that need answering about winter and her koi’s safety.

Can Koi Fish Survive Winter In An Outdoor Pond?

Koi fish can survive winter in an outdoor pond as long as it’s at least 2 feet deep, clean, an aerator is put in the shallow end, a de-icer keeps a hole in the ice, and you don’t feed them. All of the water in a pond doesn’t freeze which is why at 2 feet deep your koi fish will be fine.

Winter koi pond maintenance is easier if your pond is at least 2 feet deep

But Carol also wants to know what she would need to do if she decides to move them inside during winter.

What Do I Do If I Choose To Move My Koi Fish Inside During Winter?

If you move your fish inside:

  • Always use de-chlorinated water!
  • Have a 100-1000 gallon tank
    • Polytank or stock tanks are more durable and easier to move than glass
  • Have a small filter, aerator, and de-icer (unless it’s a heated area, then get food instead of the de-icer)
  • Set up the tank near a power source, water source, and drain for easier cleaning and filling (weekly)
  • Cover with a net so your koi don’t jump out

Following these tips will help your koi fish be comfortable inside and give you less work to do (and less to stress).

Moving your koi fish inside during winter is an option

How Do I Keep My Pond Fish Alive In The Winter?

Make sure your pond is clean. Muck and debris left in the pond break down into nasty gases that can harm your fish. But this is where the aerator and de-icer come in. The de-icer keeps a hole in the ice for the gases to escape and the aerator adds clean oxygen to the water for your fish to breathe.

Example of a deicer you can use for winter koi pond maintenance

Also, do not break a hole in the ice. That can cause your fish to go into shock and, well, die or get hurt. It would be like if you’re almost asleep and a giant hammer crashes through your ceiling.

As for feeding them, do not feed them under 50°F. Fish are cold-blooded and their metabolism relies on the temperature of the water. When the water gets cold their metabolism and digestion slow down, meaning any food they eat will just stay inside them all winter long (can you imagine the stomach ache?). From 60-50°F switch to cold water food. 

During winter, koi and other pond fish basically hibernate. Everything slows down and they basically stay in a half-asleep state.

Carol and Carter wonder what they would’ve had to do if they’d waited too long to do any winter koi pond maintenance.

Winter’s Already Here, What Do I Do?

If winter has already set in and you have fish, get a de-icer on it ASAP. Again, do not break a hole in the ice or you will hurt your fish. If you have an aerator in the pond move it to the shallow end as soon as you can reach it. 

Using an aerator to help keep a hole in the ice is a part of winter koi pond maintenance

Leave your pond running. Make sure it stays full too so the pump doesn’t run without any water going through it (it isn’t good for your pump). Look for ice dams around the waterfall. You don’t want your yard becoming a swamp because water from your pond is being channeled into the grass!

Once that is done then your pond is about as set up for winter as it’s going to get.

Carol and Carter are both glad they thought about winter koi pond maintenance before winter set in.

The Couple’s Next Steps

Now Carol and Carter need to decide if they’ll do winter maintenance themselves or hire a pro to do it. Mostly they’re just feeling relieved that their pond is deep enough they won’t need to move their koi fish inside. Their real next step (and yours) is to think ahead about spring pond maintenance.