This Wacky Weather and How it May Affect Your Fish

The weather has stayed unseasonably warm well into what is normally winter. Though lovely, let’s discuss how this will affect your koi or goldfish. 

Temperatures and Metabolism

Feeding fish is all about water temperatures. Fish are cold-blooded creatures and when the water is 50 degrees or above, their metabolisms are faster. They’ll be moving around more and will need calories. When the water is below 50 degrees, they get slower and need fewer calories. They will almost not move at all when the water is 40 degrees and below. They cannot digest food when water temperatures are this low. In fact, if you tried to feed them when the water is 40 degrees, they likely would not move to get the food at all. 

So, does that mean we should feed the fish when we have consistently warm weather in the winter? 

This is the question that has been on our minds. We wish the answer was black and white, yes or no, but it just isn’t. 

Here are the things to consider:

  1. Do you know what your pond temperatures have been and have they been 48 to 55 degrees (or warmer) for 5 days in a row?
  2. Have you checked the weather and do you know that it will remain the same for the next week? 
  3. What is the behavior of your fish? Do they swim up for food when you walk up versus sitting at the bottom, not moving? 
  4. Do you have winter fish food (low protein)?
  5. Is your pond completely without string or fuzzy algae? 
  6. Is your waterfall/biofall pump running? 

If you answered yes to all of these questions, let’s get a bit more in-depth. However, if you’re feeling overwhelmed by this, just skip it and don’t feed your fish!

  1. If temperatures have been 48 to 55+ degrees for 5 days in a row their metabolism is running and could process low amounts of low protein food. 
  2. If the weather looks like it will be holding for the next week their metabolism should continue running and could process low amounts of low protein food. 
  3. If the fish look active, this supports the idea that their metabolisms are up and running. 
  4. Potentially feeding the fish is only a possibility with winter fish food—low protein, not regular food! This is important! Also, feed them half of what you would normally feed them. 
  5. If your pond has string or fuzzy algae, they are grazing on that as nature dictates, so if there is plenty of algae there’s no need to feed them. 
  6. Whether your waterfall or biofall pump is running is important because we have to look at the ecosystem currently and how it is functioning. Remember, the plants are not doing their job right now. They’ve died back and are not really processing nutrients in the water. The beneficial bacteria is working but far less than in the summertime when the water temperatures were higher. Therefore, the stream, waterfall, and biofall, with the help of beneficial bacteria, are doing the work of processing nutrients. If these are not on right now, please do not feed your fish! There is nothing to help process the ammonia that feeding the fish would create. 

What did we do in this situation? 

We fed our fish every 3 days. We only fed half of what we normally feed them, and we used winter fish food. Our biofall was running and we monitored the temperature of the pond as well as upcoming weather. 

What are we recommending that you do? 

We are not recommending anything! We are simply laying out the facts for you to make your own decision. It is a risk to feed the fish this late in the season unless you have considered all these questions and are knowledgeable about your pond and system. 

Pro Tips:

If you think your system is having water loss, do a leak test while the weather is still warm. It is better to figure it out before the frigid winter hits. 

Evaporation happens in the winter and more so when there is warm weather. However, you should not be adding as much water to the system as you were in the summer. 

Remember, in Colorado the hose must be disconnected from the faucet (spigot) when you are done using it. This is very important as pipes can freeze and rupture if left connected!

If you are interested in installing a backyard pond or water feature, Colorado Pond Pros are the pros you should be talking to. Contact us today! We would love to set you up with a koi or goldfish pond, or any of our other pond services that suit your needs!

For more on koi and goldfish, check out our blogs Koi Food—What to Know, Feeding Pond Fish, or Can Koi and Goldfish Be Kept in the Same Pond.