One thing that often concerns koi keepers, although it really shouldn’t, is the wild temperature swings that can affect a fish pond during spring each year. Many keepers of koi and goldfish worry about the water temperature, thinking their koi will be harmed by the sudden change from cold water to warm water and back again that is so typical of these seasons.
Yet, there really is little need to worry. Koi are surprisingly hardy fish, which is why they are so popular for our fish ponds. Another reason not to worry too much is because water temperature doesn’t experience the same wild swings that the air outside will feel. Water temperature fluctuates a lot more slowly than the air does, and so if you are faced with a quick cold snap during spring, the chances are the water in your fish pond won’t drop to the same extremes.
If you are still worried, you can buy a fish pond thermometer to keep track of the cold water temperature for you. The main concern with water temperature changes, particularly a change from warm water to cold water, is that the koi and goldfish’s eating habits will change.
As water temperatures get colder, koi and goldfish will eat less, so you need to be careful when you feed them. If you give your goldfish too much food during a cold snap, it simply won’t be eaten at all, and then you could have problems of water contamination which can cause much bigger problems than pond water temperature swings.
Koi are actually quite tough when it comes to handling cold water temperatures, but less so when it comes to living in a polluted fish pond.
Controlling Fish Pond Water Temperature
If you are concerned about water temperature swings, you can install a heater to help combat any erratic warm water to cold water fluctuations. A small, 100 watt electric pond heater will reduce temperature changes in a fish pond. Don’t expect such a heater to increase water temperature in cold weather. See it rather as a mechanism to slow down cooling rather than heating which means overnight temperature drops will be less severe.
Water Temperature Swings and Feeding
During cold water temperatures, your koi’s metabolism slows down, so they will eat less. They will also be less active, meaning that they digest less of the food that they do eat, so you need to be careful of this. The reason is that less food they digest, the more waste they will excrete. This waste can build up if you’re not careful, making the fish pond water dangerously toxic for your goldfish. For this reason, it’s best to give them food that is low in protein during colder water temperatures.
Koi’s growth potential is much more limited in cold water than in warm water. Protein is the key component that spurs growth in koi, which is why during summer, when they are swimming in warm water, they should eat food that is high in protein, to maximize growth. But in winter, in cold water, the koi will not utilize this protein, and instead it will simply exit the gold fish as a waste product, dirtying the fish pond water. This by-product protein takes the form of ammonia (NH3), something that your filter can have a big problem dealing with. It also contributes to very poor water quality, so it really is essential not to feed your koi food that is high in protein when the water temperature is cold.More info at : firstname.lastname@example.org.
CROATIAN CENTER of RENEWABLE ENERGY SOURCES (CCRES)