Do you long for a decorative fish pond but lack the backyard space? Patio ponds are the go-to option for apartment dwellers, but you shouldn’t try to keep koi in such a small area. As a rule, you’ll need around 200 gallons of water per one to two mature koi fish (or two to three goldfish.) Since most container ponds are less than 50 gallons, they are unsuitable for housing koi and goldfish.
Don’t fret! You can still raise beautiful fish in a mini pond as long as you choose a suitable species. The best fish for a patio pond include tiny, cold-hardy minnows and other aquatic critters like snails and shrimp. These fish and invertebrates can be found at your local pet store or aquarium supply shop.
Minnows
Minnows are colloquially any tiny freshwater fish, but true minnows are members of the Cyprinidae family. Most minnows are social fish that thrive in shoals of at least five.
The most popular minnow for patio ponds is the White Cloud Mountain minnow, which is native to China. These fish are hardy in a wide range of water temperatures. Still, you must install a small pond heater if your pond’s water drops below 40 degrees Fahrenheit in winter and supplement aeration during hot summer days when the water exceeds 75 degrees.
Mosquitofish
Introduced worldwide to control mosquitos by eating the larvae, mosquitofish are native to shallow waters along the Mississippi River. These one-to-two-inch fish are exceptionally hardy and can withstand water temperatures below freezing to over 100 degrees. They can also survive for a period in low-oxygen environments and saltwater twice the salinity of seawater.
Japanese Rice Fish
Also known as medaka, Japanese rice fish are another hardy fish species suitable for mini ponds. They can survive water temperatures from 32 – 108 degrees Fahrenheit and are fit for both freshwater and brackish environments.
These fish are prolific breeders that lay eggs up to once per day. For this reason, they were the first vertebrates to reproduce in space in orbit aboard the space shuttle in 1994.
Shrimp
Cherry shrimp are small freshwater crustaceans that are popular in planted container ponds. These shrimp make a delightfully colorful addition to your pond while also helping to keep it clean and clear of detritus.
Snails
Black Japanese Trapdoor Pond Snails are another aquatic pet you can add to patio ponds to keep the water balanced. They primarily feed on algae and other microscopic organisms that impact water clarity. These snails are also fantastic water quality indicators since they close their “trapdoor” operculum to seal out polluted water, clearly warning of issues before fish inhabitants die.
More Fish-Keeping Tips
Do you have outstanding questions about how to keep your fish healthy and happy in your pond? Contact us today to get helpful advice from our pond experts by calling 866-POND-HELP.
Explore these related guides to learn more:
How Many Fish Can I Have in My Pond?
How Big Will My Koi Grow?
Common Pond Fish Diseases
Last Updated: April 10, 2025