27/05/2026
Looking after your Koi during hot weather.
Although it's always nice to have good weather, when the temperatures rise, we need to be mindful of the fish in our ponds. Here are some tips to make sure your prize Koi remain happy and healthy:
1) Warm water has significantly less dissolved oxygen in it, and this can put your fish at risk. To combat this, turn on all available aerators, fountains, and waterfalls to agitate the surface of the water. You should also make sure to keep your pumps running all the time.
2) Try to provide shade for as much of the pond as you can - between a third and a half of the surface where possible. This will help the water from not heating up as much and will stop white Koi from developing sunburn. Having floating plants such as water lilies will also provide natural shade.
3) In warm weather it's a good idea to reduce feeding, since uneaten food will quickly rot and lead to problems with water quality and depleting oxygen. Instead, feed a small amount once a day or in extreme heat stop feeding entirely.
4) You can change approximately 20% of the water should ammonia or nitrites increase. Should you need to do this more than once in a short period of time, then you should add a dechlorinating solution to the water.
5) In extreme heat, you can float frozen water bottles in the pond which will lower the temperature. However, NEVER add ice to the pond directly, as a sudden drop in temperature will cause harm or kill your fish.
Happy pond keeping.
