Over-Wintering
your Pond and Water Garden
Care for pond plants, fish, and pond health...
All summer long, you've enjoyed the tranquility of your water garden - beautiful foliage,
sounds of trickling water and colorful fish eagerly awaiting a handful of food. The
water garden didn't get that way by itself. You added the right kinds of plants and
fish to create a balanced ecosystem. The water gardens we create look beautiful and
sustain life because we follow nature's rules. It's the same during winter
months. Despite all outward appearances the pond is active even when the water is
cold or even frozen. Dead leaves, algae, insects and solid fish waste that have
accumulated over the summer slowly break down during the winter months. This natural
decomposition uses oxygen and produces hydrogen sulfide, a toxic gas. A build up of
leaves and other debris can produce excessive hydrogen sulfide and at the same time,
reduce oxygen to dangerously low levels. This can cause all of your plants
and fish to die besides having a very nasty looking pond next Spring.
So, what should you do to provide a healthy pond during
the winter?
First, remove all debris you can with a coarse net, which you
should have been doing throughout the year (to prevent more leaves from falling, drape a pond net over it). Next, use a
fine net or vacuum to remove
any sludge covering the bottom. Since you're in there stirring things up a bit, you
should change about 50% of the water, too. If your pond has a lot of
"junk" at the bottom of it and is tinted yellow from dissolved organic material,
make (2) 30-50% water changes a day or two apart. When you're pumping out the water,
stir up the sludge and clean the bog and/or marginal shelves, etc. After everything
is cleaned, start to fill with tap water. Run the tap water through some
Super Activated
Filter Carbon which dechlorinates the water while it's going into the
pond. If you're real concerned about the chlorinated water, add some Ammo Lock
to instantly neutralize the chlorine and chloramine in the tap water so it doesn't harm
the fish (It also locks ammonia so if you ever have high ammonia levels in your pond, you
can use the Ammo Lock). It is imperative that you get rid of the chlorine in the tap
water or else it will kill your fish. Plants don't like the chlorine, either.
Be sure not to put the chlorinated water in your biological filter such as bioballs,
lava rocks, filter pads, etc. as the chlorine in the water will kill your beneficial
bacteria you've worked so hard at achieving in order to have a clear pond (and much more).
Over-wintering koi and goldfish in your pond
The metabolism of koi and goldfish is controlled primarily by
water temperature. As the water cools, their metabolism slows down and they
require less food and food with less protein. When fed high-protein diets in
cool water, the excess protein is excreted as ammonia, and the fish can get sick and die
from the high levels of ammonia. Eliminate the high protein diets when the water
temperature gets to 60-65°F and start feeding them "Spring and Autumn Fish Food".
This type of fish food is better for the dietary requirements for the fish and
won't pollute the water with excess ammonia. Some gardeners continue to feed their
fish until they no longer come to the surface and want to be fed, while others stop
feeding the pond fish when the water falls below 50°F. Personally, I stop feeding
them when they no longer come to the surface, which is usually around 45 - 50° F, but I
feed them considerably less than what I normally do. Feed them about 20% of what you
would in the summer and you should be fine. If the fish don't eat the food, of
course, stop feeding them or else the uneaten food will only settle to the bottom and add
to the overall nutrients in the water.
For those of you who have ponds with fish and no plants, your
fish can benefit from the addition of pond salt .
Pond salt provides electrolytes to the fish and gives them a nice, soothing
protective coating. It acts as a barrier from bacteria, fungus, and parasites that
attack the fish. Use a .3-.5 % salt solution if you don't have any plants and only
have fish, and about a 2% salt solution if you have both plants and fish. For those
of you with large ponds, you can use a product called "Solar Salt". It is
99.6% sea salt and is used for water softeners. You can find it in your grocery
store. The main thing is that it does NOT have rust inhibitors or anything else
added to it and is completely natural. It's essentially evaporated sea water where
they've collected the salt deposits. You CANNOT use salt if it has additives added
to it, like rust inhibitors. It comes in a 40# blue bag and costs about $5.00 and
some change per bag. It's manufacturered by Cargill. We use a .3-.6% salt
solution for our koi ponds. This much salt ( .3-.6%) salt is ideal to use in the
Fall and Spring when the fish's immune system is compromised and some bad types of
bacterial strains and parasites are still active and growing. I will also tell you
that some beneficial bacteria may die with a higher salt solution, so be careful on the
amount you choose. You pond may not be crystal clear, but you fish can be healthier
because of it. If in doubt, just check the ammonia levels in the pond. A 2-3% salt
solution is a pretty safe bet. There are specific test kits that test for salt
levels. They are referred to as salinity monitors. You can find them here. (Make sure your
salt is totally dissolved and mixed throughout the pond before testing the water.)
After about 3 days of filling your pond with tap water, you can
add some Microbe
Lift/Autumn Prep. It is beneficial bacteria that has bacterial strains that work
in cold water below 55°F (most of the beneficial bacteria on the market only work in
water temperatures above 55°F). This will help to continue to decompose the organic
matter in your pond during the Fall and part of the Winter. If frozen, it becomes
active when thawed, so there's no need to worry about adding it if the water is very cold.
Will my fish freeze in my pond?
Well, if your pond is at least 30" deep and you live where
you may get at most, a snowflake or two and that's all, you should be fine. If you
live where there are harsh winters, you should have your pond at least 30"
deep, if not deeper. If you're just creating a pond, do yourself a favor and make
the pond 3-5' deep, and your fish will love you for it. Koi love deep water -
you could have it 10' deep and they'd really love it. They need exercise from
vertical swimming, so the deeper the better. Anyway, after the water temperature has
dropped into the low to mid 50's, bring your pump up closer to the surface of the pond so
you don't disturb the warmer water below. Still keep the pump pumping, but just
bring it up to a higher shelf or higher area in the pond. You can keep the pump on
until the water temperatures are in the high 40's. From there you can turn off your
pump and remove it from the pond as well as your filter. Clean them up for the
winter and bring inside the garage. The reason why you don't want to keep your pump
running is because the tubing which is most likely on the outside of your pond will start
to have ice form within in it and will eventually freeze solid and cause your pump to burn
out. When you remove the pump you will need to put in an ample size aerator in the pond. This will
provide oxygen to the fish during the winter. You will also need a pond de-icer which will keep an
area of your pond's surface "open" and from freezing solid. This provides
an opening for the toxic hydrogen sulfide gases from decomposing fish wastes, organic
matter, etc. to escape and an entrance for oxygen to enter. We have a lot of information on our site as to
which de-icer you should use. If you're reading this "a little late" and
your pond's surface has already frozen, DO NOT go out and try to hack a hole in the
ice. You just may hack into one of your fish! A neat little trick is to get a
pan with a handle and attach a long string to it. Fill the pan with boiling water
and set the pan on the ice. The heat from the pan of boiling water will melt a hole
in the ice and you can retrieve the pan with the string! :o)
If you have a shallow pond or even a small preformed pond and you have small koi or
goldfish less than 6" long, you really need to bring them either inside your home or
you can keep them in an unused, untreated kiddy pool or aquarium set up in a cool basement
or garage. All that is required is an small aerator to provide oxygenation.
A nice, small but efficient aerator is our Ornamental Pond Aerator.
If outside in the garage, the fish may not need to be fed, depending on the water
temperature (above 45°F or so). Put in about .3-.5% pond salt solution,
too (start with .3% and then slowly add more up to .5%. You may need extra aeration during
this time). This will give them a protective coating and help them adapt to their
new surroundings plus eliminate some bacteria and fungus that can attack them. You should
monitor the ammonia, pH and nitrite levels weekly especially if the fish are fed.
(If you do plan on feeding the fish and IF they eat, you will need a filtration system and
pump for the temporary pond/aquarium too so they don't die of ammmonia poisoning).
Small water changes, about 20% each month will keep the water in good shape until
Spring. Koi are "jumpers" and will jump out of the pool/aquarium so be
sure to cover it with the netting.
This is a must or else you'll wake up one morning and find your dead koi on the floor
beside your aquarium.
Some of you with small backyard ponds may not find it practical
to bring the fish inside for the Winter. What you need to do then is have a de-icer and an aerator in the pond. If your
fish are less than 6" long and your pond is less than 30" deep, I would suggest
a submersible de-icer. The fish will need to huddle around the de-icer to keep from
freezing. The de-icers will only turn on when the water reaches 40°F. It is
thermo-regulated by the manufacturer. By having a de-icer you're just keeping an
area within your pond from freezing. We have actual heaters too, but they are quite
costly and expensive to operate. They are used primarily for aquaculture methods but
you can find them here.
Those of you with large ponds, like the size of 1/4 of an acre or
larger can benefit from an aerator
during the winter months (and of course, summer months, too!). Aerators take very
little energy and help to continue to decompose leaves and organic matter in the
pond. You don't necessarily need a pond de-icer to keep it open as there is a
large amount of water in your pond. The proper size of aerator will help to keep an
area of the pond "open" as well. Aerators should ideally run 365 days a
year.
Last but not least, over-wintering your aquatic plants...
Long after the impatiens have been pulled out, water gardeners
are still hoping for that last lily to bloom before the snow starts to fly. We want
to see just "one more blossom" before things get cold and yucky. Well, if
you want your hardy plants to come back next year and make your water garden look
beautiful again, this is what you should do:
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