How Many Pond Fish Should You Have?


Adding pond fish is like eating french fries, it’s hard to stop after just one. When visiting your local pet store or water garden center, its difficult not to take home another goldfish or koi that’s just staring up at you sweetly. They’re so cute! 

But, like all things, there’s a limit to how many pond fish you can have. Too many fish in a pond can lead to a poor environment for fish and a breeding ground for algae. The more pond fish, the more waste they produce in your pond. That waste turns into fertilizer for algae and unless you have the filtration power to pump it out, you’ll end up with that yucky green pond water that detracts from the beauty of your property. 

Before you buy a plethora of fishy friends, use these tips below to figure out the maximum amount of new outdoor pets you can comfortably fit before you start running into pond problems. 

Pond Size

Measure the dimensions of your pond in feet to start, then use this formula to gauge the capacity of your pond. Length x Width x Depth = cubic feet x 7.5 = gallons. If you need help with the math, use there’s many helpful online calculators like this one! Its recommended to give 200 gallons of water for every 1-2 koi fish or 2-3 goldfish, so if your pond is 1000 gallons, you can have up to 10 koi fish or 15 goldfish! 

Allow Room to Grow

Its important to remember that like all other living creatures and plants, fish grow as they mature in age. So, if you’re starting out with young or adolescent fish, don’t immediately jump to the max amount of fish you can have in your pond. Start with a low number of fish since a 2 inch fry will grow into a 10 inch adult before you know it! You can always add more fish in the future. 

Add More Slowly

Your pond will need time to build up a biological filtration system full of beneficial bacteria to handle the new introduction of fish to its ecosystem. This means that when you start adding fish to your pond it is best to go slowly and add only a few at a time. 

Keep Up with Routine Maintenance 

After your fish have successfully moved in and your pond has had a chance to adjust, there’s routine maintenance steps you should take to keep both fish and pond happy and healthy. Use natural bacteria like PondShock or Seasonal Defense to help break down fish waste and other debris, give your fish some shade with aquatic plants that can float or be submerged, and most importantly feed your new fish a healthy diet with the right amount of protein to ensure their health. 

Share or Upgrade

If your pond is already overpopulated, don’t fret! You have some options! You can give a few fish to a fellow pond-owning friend, or if parting with your adorable fish is too emotionally difficult, you can upgrade your filtration system or your pond! 

Using an external pressurized filter can make handling waste even easier, or if you want to upgrade your whole water feature and pond, contact your local pond contractor for more information! Our team of experts at Aqua Landscapes are happy to provide all the information necessary to help you create an outdoor space that’s perfect for you!  Contact us for more information.

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