Published on: August 26, 2021
Fish kill or fish die-off is a widespread problem for many pond owners, but it’s not just from the winter freeze. Fish kill can also occur in the hot summer months, and we want you to know how it can be prevented.
Many pond owners have experienced winter fish kill, and the cause is well known. In the winter, ice and snow cover the pond which blocks sunlight from penetrating into the water, limiting photosynthesis. When this happens, there is a lack of oxygen that is being produced; water is cold, oxygen is low, fish are in a stressful state and many can die.
For winter we have the ideal solution. Natures Pond Conditioner Fall/Winter blend cleans ponds of runoff, debris and decomposes organic matter before the freeze up. Paired with 'bottom-up' aeration which oxygenates the pond, the risk of winter fish kill can be dramatically reduced.
So, if lack of sunlight is the culprit in the winter, why does fish kill happen in the summer when sunlight is abundant? One cause of summer fish kill could be a result of the treatments you use. Herbicides and algaecides are common practices for some pond owners but are far from the best solution. These products are designed to kill unwanted aquatic plants and algae to clean the pond. But killing the plants with chemicals actually adds fuel to the fire of your pond problems. When the aquatic vegetation dies it sinks to the bottom of the pond, adding a layer of organic matter and sludge that must be consumed by the natural bacteria in the pond.
Bacteria are living organisms that require oxygen, so when it is working hard to consume the organic matter its also consuming lots of oxygen from the pond. All the aquatic vegetation has been killed, and there is nothing to produce oxygen in the pond. The now oxygen-depleted pond can easily cause a fish kill.
Another cause of fish kill in the summer could be due to stratified pond water.
In the summer, the bottom layers of a pond have less oxygen than the top layer. Fish spend most of their time in the top layer. If a summer storm hits the pond, wind and rain can stir up the pond, de-stratifying the water. When the two layers are mixed, oxygen levels can be lowered dramatically. (Fish growth and activity usually require 5-6 ppm of dissolved oxygen)
What can pond owners do to prevent fish kill in the summer?
Whether it's caused by herbicides, algaecides, or stratification, a lack of oxygen is the main cause of summer fish kill in a pond. The best solution is consistent bottom-up aeration that restores and sustains pond oxygen levels. The bottom-up motion that aeration creates can also prevent stratification of the pond temperature and limit algae growth.
Instead of tackling unwanted aquatic vegetation with herbicides and algaecides, manually remove plants and weeds with a Cutter n’ Rake. This way, organic matter will not be added to the bottom of the pond. Nature's Pond Conditioner Spring/Summer formula can also be used.
Leading up to the Summer and then in the Fall, are the best times to implement a care program to prevent problems like fish kill before it's too late. Nature’s Pond Care 3-Step Program is proven to reduce the risk of fish kill and keep ponds clean and clear all year round.