The Only Koi for the Summertime Blues

Today in the Koi Corner (we're refusing the misspelling alliteration opportunity there) we've rounded the corner into summertime care. While it is still spring in much of north America, our southern reaches are solidly into consistent warm weather. This is the season where all our spring and fall work are enjoyed and we get to spend the time around our ponds. It's also a time to pay attention to them and make sure they're staying healthy as they increase in temperature and sunlight availability.

The number one item to pay attention to this time of year is temperature management. Koi do best when their homes stay between 65 and 75 degrees and most other tropical fish you'd think about having in a pond are similar. You can tune all this advice for the temps your fish will do best in. For most of us, it's pretty unlikely that we'll need to heat the ponds during this time of year, but keeping them cool can be a challenge, especially for those of us who live in hot climates and / or have ponds in areas that don't provide much shade.

Planning your pond thoughtfully is the best way to alleviate heat related challenges. If you happen to live in areas where the average temp is more than 80 for a good portion of the year, then maybe Koi shouldn't be your number one choice. For the sake of clarity, we mean average of day and night, not peak daytime temps. Fish like Amazonian Catfish, Pacus, Arowanas and others with monster growth potential can do great in hot weather ponds.

If your average temperature stays below 75, you're going to be better off, but a long heat wave could also have negative effects on your fish. As water warms up, its capability to hold oxygen (or any gas) decreases. Warm soda goes flat faster than cold soda, and a warm pond holds less oxygen than a cold one. Hopefully, your pond gets some shade during the warmest months either from structures or leafy trees (a mixed blessing when those leaves fall in the, well, fall.) If you're still in planning phase, and you think it's likely that your pond could get warm, think about making it deeper than 2 feet, at least in a large portion of it. Deeper ponds have more volume and will resist warming better, and less light gets down there, helping it stay cooler as well.

If it has been hot for a few days, and you notice your fish acting sleepy or gulping at the surface, take the temperature of the water and if it is higher than your specific fish like, take proactive steps on their behalf. Think about using temporary structures to at least partially shade your pond, especially from high noon or long afternoon sun. You can use things like pergolas or umbrellas to do this job in the short term but perhaps think about planting some shade providers for long term temperature protection. You can also turn to forced oxygenation via air stones or water features. Anything that disrupts the surface and moves water will increase the level of oxygenation and help keep the temperature down.

If temperatures in your pond go north of 85 degrees, you'll need to take some immediate action, especially for Koi who won't live that long at that temperature. Do some large water changes and stop feeding until the temperatures come back down. Find some way to get some of your pond shaded right away. In extreme situations you might think about removing some fish to decrease the oxygen demand.

Another issue that people come up against is also fueled by sunlight, and that is algae blooms. These can range in severity from a merely aesthetic issue to a serious challenge. The biggest problem algae present is that it compounds the oxygenation issue in warm water. The algae love the warm environment, and while it produces a lot of oxygen during the day, it steals it at night. It also dies and starts to decompose quickly which further decreases the oxygen available for your critters. Reducing the amount of light your pond gets will make the most dramatic difference in reducing the algae.

Some pond keepers recommend adding dye to the pond to reduce light penetration, keeping the pond cooler and reducing algae growth. We've found it to be ineffective at keeping temps down, but it does inhibit algae growth and is useful for hiding your fish from predators. Conversely, it also hides your fish from you...

Algae can be partially controlled through good maintenance. Test your pond regularly to make sure you aren't having nutrient spikes. Nutrient issues should be addressed by how much food you're using, how that food is being delivered, and perhaps how many fish you have. Using an auto feeder will control the urge to over feed, and can deliver food throughout the day, making feeding / digestion more efficient. Sometimes you just have too many fish for the volume of water you have and the strength of the filter system. You can add beneficial bacteria to your system to enhance the filtration and reduce the amount of detritus. Products like Dr. Tim's Waste Away and One and Only are both available in pond sized containers and can make a huge difference.

While summer is for watching the pond, it's also a time to be taking care of it. Top off the water as it evaporates (which will also help control temperatures). Remove anything that gets into the pond and doesn't belong there, like your brother-in-law, or more commonly, branches and pinecones and stuff. Check your filter to make sure everything is running effectively and efficiently. Check on your pumps to make sure they are clean and clear, and nothing is blocking their intake which will reduce the flow as well as the life of the pump. If you haven't already, you should probably add (and maintain) a UV Sterilizer that is rated to handle the size of your pond and pumps. You can see our article on UV sterilizers for your pond here: https://www.qualitymarine.com/news/for-the-cleanest-clearest-healthiest-pond-go-uv/

The season is here to enjoy your yard, and especially your pond. Keep up the maintenance. Watch your fish carefully. Keep that pond clean and give it some shade and enjoy it with your friends and family while the weather is still nice. If you're headed to the Pond Store or your Local Fish Store to get some new Koi, always ask for the best quality fish around, ask for Aquatropic.