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Your Fish and Colder Weather

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You see a lot of blog posts and guides about the basics of preparing your pond for winter:

  • Clean out fallen leaves and any debris
  • Trim your plants
  • Remove UV lights and pumps if needed.
  • Cover with a net.

What I am going to cover today is what I do to try to keep my fish healthy over the winter. I know that the cleaner my pond is going into the cooler season the better. The more balanced the water is, the less stress on my fish, and that decreases the susceptibility to parasites and disease. Doing a partial water change can decrease the concentration of nitrates. Nitrates are what are left behind after the good bacteria break down the decomposing leaves and excess fish food. Did you know that the summer biological filtration gets less efficient when the water temperature gets below 68 degrees F? It pretty much quits working when the water temp drops below 42 degrees. I use a cold water bacteria; that helps for longer. Remember: the healthier the water, the better it is for your fish!

I stop feeding my fish when the water gets to about 55 degrees (I depend on my thermometer alot in the fall!). If they are still active and seem to want to eat, I switch to a cold water food that is easier to digest. If the water temp falls below 40 degrees, I completely stop feeding them. The fish’s metabolism slows down and their stored reserves will last them through the winter.

I leave my fish in my pond over the winter- one area of my pond is over 18 inches deep. Some types of fish don’t like cold weather.  Fancy tailed goldfish, lionhead and bubble eye goldfish are some that might like to be brought inside for the winter. The warmer water sinks and the top layer of cooler water acts as insulation (time to move your areators up to a plant shelf so that they don’t stir up the cold water).

I live where my pond doesn’t freeze so I don’t need a de-icer, but if I lived further north I would need one. It is very important that your ponds surface doesn’t freeze over. The harmful noxious gases need to escape and your fish need to breath. Never break the ice on your pond, the shock waves can hurt or even kill the fish.

I know how I love my fish (although I don’t name them – except for Bob). I am hoping that this spring will find everyone happy and healthy again.

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