Pond Heating in Winter

Many pond fish die every year because there is no pond heating in winter and the water is colder than 4 ° C. This often occurs in the first few months of the new year. Why is that even though the winters always seem to be milder? In this post, you will learn the reasons.

The goldfish and its origin

The birthplace of most pond fish is one of the thousands of breeding facilities that are factory-set up in various countries around the world. The goal of the breeder is of course to work economically. This presupposes that the mother animal spawns in large numbers, as many eggs as possible are inseminated, many of the eggs “get through” and finally grow very quickly to retail size. Because growth and metabolism are stunted at low temperatures, most growers heat the water in the facilities. This guarantees an even development of the young animals as well as better defenses of the body against possible pathogens. Most animals do not know a real winter cycle from birth. Even the parent animals have already lost their natural defense reactions against cold and parasites in the course of keeping them under optimal conditions.

Are our fish warm showerers?

Only at a pleasant 24 ° C do the goldfish and especially the Koi feel “at home”. The circulation is vital, the digestion of feed is highly active and the immune cells can draw on their full potential. The cold-blooded organism is totally dependent on the ambient temperature so that it can get particularly tight in winter as soon as the freezing temperatures last for weeks and the pond is structurally unfavorable at the same time. This tends to be the case more and more often as the gardens are getting smaller and the desired pond is created where there is space. Often the location is in the clear field of vision of the terrace, balcony, or living room and therefore free of protective trees or other surrounding vegetation. The wind has a free path and cools the water down unhindered by the evaporation cold, which is unfavorable for the fish.

The incidence of cold rain and snow could also be reduced by a rather marginal location of the pond in the garden. If the pond has a sufficient depth of around 1.40 m or more and a minimum volume of around 15,000 liters, it usually maintains a minimum water temperature of 4-5 ° C on the substrate. Smaller and particularly shallow ponds cool down more, as less water also means less heat storage capacity. The fish symbolically get “cold feet”, suffer from a lack of energy, and are significantly more susceptible to parasites. This is what makes pond heating so useful in winter.

The Back and Forth at Freezing Point

In recent years, the winter periods have been technically unstable in terms of temperature. The weather doesn’t seem to know what it wants. Even in the deep winter months, we measure constantly changing values between -5 and +10 degrees Celsius. These enormous fluctuations not only disturb us but also the natural rhythm of the fish. So it happens that the organism constantly switches between the modes “wake up” and “fall asleep”. An enormous burden that shows severe after-effects – especially in spring.

The solution: pond heating in winter

Heating the pond does not mean that we should create tropical bathing temperatures and use the pond as a bathing pond in winter. It means that we gain control over the behavior of the temperature and ensure that the fall of cold does not happen too quickly in autumn and that spring does not wake up too quickly in the new year. In autumn it can get very mild again for some time when spring shows the freezing cold shoulder after the first buds have sprouted.

One method of pond heating in winter that makes the most biological sense is to install an automatic system. This regulates the desired and individually adjustable water temperature that suits the respective season. These devices are called, for example, instantaneous water heaters, which you operate using a digital or mechanical thermostat function. There are also simple thermostats with remote sensors that switch on a separately connected heat source, e.g. a floating heater if required. There are inexpensive ways to insulate the surface of the water so that valuable thermal energy is not lost too quickly. This can consist of translucent bubble wrap with “food approval” or of transparent Isoballs, which are laid out over a large area and have a strong heat-separating effect.

The ideal temperature profile …

… depends on several factors. The water volume, the location of the pond, the region where you live and the available heat generators play an elementary role in setting the temperature profile. In general, however, you can use the following rule of thumb:

From October you should measure the water temperature about daily. As soon as the temperature drops below 15 degrees, you can install insulating insulation. Since the low point of winter is to be expected from December to February, you should now lower the temperature in a controlled manner by around 1-2 ° C per week. The pond water must not be colder than 6 ° C (measured on the substrate, use an extension for measuring if necessary). Excessive water movement must be prevented at very low outside temperatures so that the water does not cool down too much and the warmest zone of the water is on the bottom. You will certainly notice that the animals remain a little more active when the water is heated. This has the advantage that the fish’s immune system continues to work.

Occasionally, you can try sinking feed to see whether your animals will go to the food. If so, then you should treat them to this too, because then it is a sign that they are starving and need energy. Use these small and infrequent feedings to give a little vitamin concentrates (drizzle on the food) and to check the general condition of the fish. Changes in body shape (emaciation, open wounds, etc. can be easily recognized here).

In the spring you let this process run backward. With every new week, you can heat the pond by around 1-2 ° C until the outside temperature no longer falls below 12 degrees at night. The feed should always match the water temperature. Winter food is really only intended for the icy months, a spring food for temperatures between 8 and 12 ° C, and an energy food with proteins for the warm summer.

Last but not least

If you prevent the water from freezing with a pond heater, you reduce the risk of pond liner damaged by ice sheets to 0 and, in the best case, save yourself a lot of work and money. The energy costs used are far cheaper than the “repair measures” or “healing measures” if you freeze equipment, the foil gets a hole on the edge, or fish is very weakened or even found dead in the pond as soon as the ice thaws …

With good pond heating in winter, you guarantee the survival of your animals!

Mary Allen

Written by Mary Allen

Hello, I'm Mary! I've cared for many pet species including dogs, cats, guinea pigs, fish, and bearded dragons. I also have ten pets of my own currently. I've written many topics in this space including how-tos, informational articles, care guides, breed guides, and more.

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