Overwintering Goldfish

TOTAL INVESTMENT:    $30 (every couple of years)
TIME:                                 2 hours
DIFFICULTY                     Easy
NET RESULT                     Fish survive the winter

I happened upon this blog subject by chance.  I'm a fish kind of guy, but I've always had "inside" fish.  Not "outside" fish.  I've got experience with outside dogs and cats, but never goldfish or koi.  When I met my wife, she had a giant fish pond in her back yard, and I had a giant fishtank in my house (well, maybe 2 or 3).  We sold our homes and bought a new house.  Long story short, we now have a pond in the front and back yards, and now I take care of them in the winter.  I'll leave out the part where a giant frog ate $50 worth of Koi in the front yard, a Blue Heron enjoyed a $50 dinner in the back yard, and also the part where the pump did a rather effective job of distributing 100 gallons of water into our back yard (make sure your pump sits at least 8 inches above the bottom of the pond).  Those are all good stories, but you're probably here to see how our fish survive the winter.  Can they really do that?  They sure can.  Read on.



Net

The typical year in Kentucky has about 6 weeks of bitter cold weather, but goldfish and Koi are pretty tough.  The process usually starts around Thanksgiving.  First, you need to stop feeding them.  Cold blooded dudes can't process food under about 60 degrees.  If you feed them, they can die.  Seriously.  Don't worry, their systems really slow down in the cold weather, and they do just fine.  You also want to stop all your waterfalls and empty any filters that don't sit in the water.  I take the extra step of blowing water out of the hoses with my air compressor.  I also install a net over the pond and secure the net with heavy rocks.  Remember the Blue Heron?  He doesn't like the net. 

The next part is actually runs contrary to everything you'll find on Google if you search "overwintering goldfish".  I use air pumps to oxygenate the water.  I get the cheapest units I can find with 2 outlets at Walmart (about $10) and air stones from the same place (about $5 for a pair).  They die about every 2 years, but they work great.  Think the bubbles put O2 in the water?  Nope.  The bubbles agitate the surface, and oxygen is naturally absorbed into the water.  Your fish will die if the surface of the water sits still or freezes.  Well, with one exception.  If you have a big pond that is over 3 feet deep, it can freeze for a while, and the fish will survive.  Now for the Mythbusters part.  Everything I've read on the net says that condensation will form in the tubes from the pump to the air stone.  The condensation is supposed to freeze and stop the pump.  In my experience of 6 straight weeks of sub 20 degree weather (and 8 seasons of taking care of these guys), this has never happened.  Do the air bubbles really keep the water from freezing?  Not all the time.  What in the heck do you do?  I've got a trick.  Keep reading.

 

Air Stone

Air Pump

I've read about people installing heaters to keep ice from freezing over the pond.  Maybe you need something like that if you live on the north pole, but electricity is pretty expensive to run these things.  The main goal is to keep the pond from freezing over solid.  The fish don't need to stay warm.  They're designed to survive the cold.  A little hole in the ice will let plenty of oxygen into the water.  In most cases, you don't need a heater.  You just need a big rock.  The bubbles actually do a pretty good job of foiling mother nature's plans of freezing your pond over.  When the pond does freeze over, just break up the ice with a rock or hammer.  You'll need to take out the ice chunks and throw them in the yard.  The pond freezes quicker if you leave the ice chunks in the water.  If you throw a lot of ice into the yard, fill the pond back up with a 5 gallon bucket of tap water treated with a dechlorinator like Amquel. 

Do I really need to check my pond every day?  Definately.  I've been known spend a week in Belize during the winter, and I always assign a designee to break ice for me.  Getting somebody back home to break ice in return for a wooden bowl or t-shirt from Belize is much cheaper than replacing $100 worth of dead fish.  I know they're only fish, but I'm a little attached to them.  GFCI outlets have also been known to trip, so you need to regulary check your ponds even when the weather is above freezing.


The configuration of my front pond allows me to simply unhook the waterfall and continue to run the water pump and biological filter all winter.  They get special treatment, because I also hook up the pump and air stones just like the pond in the back yard.  In the front, I have a flat rock installed for the fish to hide under, so I don't put up a net.  The herons haven't figured this one out yet.



Pond in front yard

To summarize: 

• No waterfalls (they freeze easily and all your water pumps out into the yard)
• Cheap air pumps and air stones to agitate the water surface
• Keep out the birds (net or hiding place in the water)
• Check your pond every day and keep the ice broken

I haven't lost one fish using this method.  No bourbon needed in this story?  Nope, just a couple to write it. 

 

Interested in how we built a pond waterfall?  Click here.

Click here to read about how I keep all the landscape lighting working.

Read this article to find out about taking care of indoor fish.