Winter Fish Kill Prevention: Reducing Winter Muck and Decaying Weeds and Algae

In the summer, lakes and ponds are thought of as scenes of constant activity, teeming with fish, frogs, turtles, snakes, bugs, and humans. But when colder weather comes, pond dynamics change drastically and an improperly cared for body of water can become an uninhabitable environment in a very short period of time.

Fish that spend the spring and summer splashing around their playground slow down as the temperature drops. These cold-blooded animals settle into a type of hibernation known as torpor. They become lethargic and hide among the pond’s weeds. Reacting to the change in the weather, aquatic creatures stay down near the bottom of the lake or pond, where the water is warmest. Many species of frogs and turtles bury themselves in the mud at the bottom of a lake for the winter months. These amphibians alter their activities to survive the coldest time of the year, but sometimes even their instinctual behaviors are not enough.  Depleted levels of oxygen and degraded water quality of the water in winter can lead to the death of these organisms.

What is Winter Fish Kill?

“Winter fish kill” occurs when a pond is completely covered with ice and a layer of snow. The fish hunkered down at the bottom of the pond are using up the oxygen in the water, and this “winter fish kill” can happen when their supply is not replenished in time. Normally, light coming in through the ice would cause photosynthesis in the plants in the water, and replenish oxygen needed by fish. If the pond or lake is kept dark because of a wintery mixture on its surface and light cannot get through, the plants cannot oxygenate the water and the fish can die. It is conditions such as these when pond weeds fail to save the fish hiding in their undergrowth. While plants are essential for life in an icy lake, non-aquatic plants can also cause a detrimental level of muck on the bottom.

Nutrient accumulation exacerbates the problem.  Leaves from trees and bushes around the lake fall into the water and decompose over the autumn months. Unless a pond has a leaf-catching net over it, these decaying leaves produce gases that can be toxic. If there is not a layer of ice on top of the surface of the pond, the gases will escape into the air. On the other hand, gases that are trapped under the ice can be poisonous for the creatures living below. The decomposed foliage and gases contribute to the layer of muck and the quality of the pond water at large.

How to Prevent Winter Fish Kill

Fortunately, there are ways to prevent things like “winter fish kill” and organic sediment accumulation through the winter. CLEAN-FLO’s diffused aeration systems and products such as Winter Warrior will prevent winter fish kills, and establish an aerobic environment for all aquatic life while helping reduce the non-living organic muck at the bottom all winter long. Winter Warrior, along with our oxygenation system reduces the amount of muck at the bottom of the pond or lake and improves the overall water quality. This muck reduction means that the fish at the bottom will be exposed to less noxious gases from the decomposition of organic matter, and have a better chance at surviving the winter. Taking action to reduce nutrients and muck in the winter puts your pond a step ahead in the spring.

Even though Winter Warrior reduces muck and increases the biological efficiency of your pond, it cannot save fish if the surface completely freezes over.  Aeration systems can also be helpful because they the pond or lake oxygenated when plants might not be getting sufficient light for photosynthesis to occur. CLEAN-FLO makes Inversion/Oxygenation Systems that can provide the necessary inversion and oxygenation in a very efficient package. A CLEAN-FLO system will keep an open water area in the ice all winter long so that oxygen transfer can occur all winter to prevent fish kills and improve the biological activity of Winter Warrior.

Like all ecosystems, ponds and lakes go through cycles. The energy of summer is followed by a decrescendo of activity in the fall. Pond owners should not fear the coldest season. Having a clear plan of how you are going to protect your pond is crucial. Relying on products from pond experts takes some of the stress out of the process and assures an even better spring for your pond.

For more information on how you can prevent “winter fish kill” and ensure that your body of water is prepared for spring, contact us today!