Use Aeration to Protect Your Fish This Winter

February 1st, 2018

Frozen Pond

Written by Industry Expert Joe Holz, International Sales Manager at Kasco Marine

As we continue through the cold, winter months, protecting your fish should be on your top priority list. Many pond owners understand the need to have good oxygen levels to maintain a healthy, thriving fish population, however, most only think about oxygen levels during warm, summer months. Winter oxygen levels in areas that ice over can be just as, or even more, critical than during warmer times of the year. Low oxygen levels and the buildup of harmful gases over the winter can create dangerous conditions for fish in your pond.

Ice Cover, Fish and Plants Once a pond ices over in the winter, only small amounts of new oxygen can be introduced to the system. Some plants may be able to survive as long as snow and ice cover doesn’t block the sunlight and they will give off some oxygen through photosynthesis. However, that amount is often limited and can stop altogether if snow cover blocks most or all of the sunlight.

Metabolism of fish and other pond inhabitants does slow in the cold water, limiting the demand for oxygen and preserving the oxygen longer than during warm water. Lower demand can prolong the life in the pond, but long winters or ponds with high fish populations can create critical situations as winter drags on. Decreasing oxygen levels can be deadly for fish. If levels drop low enough, fish health can suffer and may eventually die.

Harmful Gas Buildup Often just as deadly and just as common is the issue with the buildup of harmful gases. While biological processes slow, they do not stop altogether. The byproducts such as CO2, methane, sulfur compounds, etc. can build up to toxic levels if they are not allowed to vent out of the water into the atmosphere.

Kasco Marine

Keys to Protecting Your Fish Your best defense to prevent fish kills is to keep and maintain a small, open water area. As little as 1-2% of the surface area needs to be kept ice free to prevent winterkill. Simply opening a small area will allow enough life-sustaining oxygen to absorb into the water. Cold water has the ability to hold a lot of oxygen, much more than warm water. Equally as important is the ability for harmful gases to vent off into the atmosphere.

Most ponds or lakes are best served with diffuser systems to maintain open water. Placed near deep water is best and the average open water area is roughly 3 ft. in diameter for every 1 ft. of depth of diffuser placement. Best practices also include keeping the diffusers close enough to shore to maintain open water right next to land. This is for safety of people, animals or pets that could fall into the open water. If water is open up to the shore, they can simply walk out. It’s also a good idea to post warning signs near open ice or even fence off the open area.

Kasco Marine is a world leading manufacturer of decorative and aerating fountains, surface aerators, diffused aerators, municipal products, circulators, de-icers, beneficial bacteria and pond and lake dye. Kasco offers these products to endless aquatic industries such as residential ponds and lakes, water treatment plants, retention ponds, docks, marinas, fish farms, and many more. Click to view the original article

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SOLitude Lake Management is an environmental firm committed to providing full-service solutions that improve water quality, preserve natural resources, and reduce our environmental footprint. Our services include lake, pond, wetland and fisheries management programs, algae and aquatic weed control, mechanical harvesting, hydro-raking, installation and maintenance of fountains and aeration systems, water quality testing and restoration, bathymetry, lake vegetation studies, biological assessments, habitat assessments, invasive species management and nuisance wildlife management. Services, consulting and aquatic products are available to clients nationwide, including homeowners associations, multi-family and apartment communities, golf courses, commercial developments, ranches, private landowners, reservoirs, recreational and public lakes, municipalities, parks, and state and federal agencies. Learn more about SOLitude Lake Management and purchase products at

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