Getting Ready for Winter

[jfdeneve]

Having recently moved from Chicago, I’m finding the DFW winters are much more agreeable. Although last year I did lose a number of fish during the winter for some reason. The temperature swings can be significant here, from 60F in the day to 20F at night. I think the large temperature swings stress the fish and may have contributed to some of my fish dying. This year I made some changes to how to prepare the pond for winter. For one thing, I don’t have a way to bypass my water falls so I had to create my own bypass solution. The reason for bypassing the falls is to try an maintain as much heat as possible when the temperature drops below freezing. All of the water flowing over cold rocks creates a ‘cold sink’ making the pond colder when the temp dips. I also decided to add a bucket heater that I plan to place close to where my fish congregate. I know I won’t be able to heat the whole pond, but I hope to give them a warm spot when it gets cold. I plan to use a smart switch to control the bucket heater. Lastly I will be covering the pond with a 40% shade cloth to try and keep the small leaves out.

Unlike last winter, I will also test the water parameters on a regular basis.

 

[TheFishGuy]

Sounds like a nice plan!

Others will have opinions ins on stuff like heating but I will ask,

did you have a question? If not that’s fine, just didn’t want to miss it

 

[jfdeneve]

Added shade cloth and a feeding slot. Highly recommend shade cloth instead of netting if you tree that drops a lot of small stuff.

 

[brokensword]

depending on how deep your pond is, and of course volume, the water temp doesn't change as fast as the air temps do. What you'll find is you need a minimum of 5' depth to see any 'thermoclines' and genearally, closer to 10-13' in lakes. You can minimize any sudden water temp differences by lifting your pump to nearer the surface and slowing the flow (waterfall). Only if you have a very strong water flow exchange will you get detrimental temp changes. That is of course, assuming you have decent depth. Under 2' is much more susceptible than 3' and deeper.

I doubt you lost fish last winter due to temp but more probably, overload of fish relative to both surface area and pond volume. Cold water holds more oxygen than warm. Also, if your pond iced over at all and you had decaying organics, the gases emitted needs to be released or it can be toxic to the fish. What is your pond volume and fish bioload?

The fish will congregate around your heater, but you may want to watch the monthly billing on that. Gf and koi are able to handle near freezing water, so...

Hope this helps.

 

[Mmathis]

The water temperature is going to change more gradually than the air temps. Our winters (NWLA) are very similar to yours. I’m sure I get more stressed out about it than my fish do.

 

[jfdeneve]

We don’t get ice here, so pond was open to air last winter. I had 13 fish about half gold fish, and half koi last winter. 2,000 gallon pond. My guess is the decaying organics caused the probelms. Had the pond covered by a service last year. This year spent a lot of time cleaning, and put a much tighter weave cover to stop all of the small stuff from falling in the pond. I currently have 16 fish, half are goldfish, the other half are koi.

 

[brokensword]

We don’t get ice here, so pond was open to air last winter. I had 13 fish about half gold fish, and half koi last winter. 2,000 gallon pond. My guess is the decaying organics caused the probelms. Had the pond covered by a service last year. This year spent a lot of time cleaning, and put a much tighter weave cover to stop all of the small stuff from falling in the pond. I currently have 16 fish, half are goldfish, the other half are koi.

how large are the koi? General rule of thumb is 1000 gallons for the first koi, 250 gallons for the next. It might be you're overstocked. There's a website graph showing how much koi output relative to their size, but I don't have it at the moment. I believe @Lisak1 has it though...

If your pond is always open, the decaying organics shouldn't have done damage re toxic gases but as the temp goes down, the bacteria slow/go dormant/die, so it may still have been a leaf/muck problem. Keeping the bottom as clean as you can is always beneficial. Are you keeping the water flowing all winter, too?

 

[Lisak1]

Here you go:

Koi Length and Weight - Ammonia Produced, and Waste Produced

This chart also lists koi weight by weight and how much ammonia and waste they produce. Koi get heavier as they grow and produce more ammonia and waste.

russellwatergardens.com

Always very interesting to compare what you'd expect from six 3 inch goldfish versus one 18 inch koi. The biomass increases exponentially as the fish get bigger.

 

[jfdeneve]

The weather predictions here in Dallas are for extreme cold. I already have one 1,000 Watt bucket heater suspended in the deep end of the pond and I’ve been able to maintain 45ish degrees in mid 20F at night. Today I added a 1,500 Watt heater at the skimmer intake In preparation for the cold to come. Hope it does the job.