Fish For Outdoor Ponds

Thinking about adding a pond to your landscape or investing more in what you already have? If you’re thinking about adding more fish to your pond, we advise you wait until your pond has been eating for a few weeks or late spring. This allows your fish to have an effective immune response should something come in with your new fish. But you were planning on quarantining any new additions for 4-6 weeks, right? Just because you purchase your fish from a “reputable dealer” does not mean your fish is guaranteed healthy!


Best Fish Options


Descendants of the common carp, koi are made for outdoor living. They can tolerate a wide range of temperatures and are very hardy fish. The biggest problem with koi is that those cute 5-7″ babies can top out to over 2′! Make sure you have enough room in your pond for those babies to grow into behemoths.


Just like breeds of dogs, there are may breeds of goldfish. The ones that make a good living in ponds are the long-bodied, non-fancy varieties, commonly known as comets. Sarasas and shubunkins retain good swimming ability, but are usually overbred. In a pond, you can expect your goldfish to grow very large. Even kept inside, goldfish can grow roughly the size of a small dog.


Hi-Fin Sharks

A newer arrival to the pond scene, High-Fin Sharks (Myxocyprinus asiaticus) are carp cousins to the koi and goldfish. Although they may start with white and black bands, adults typically take on an all-black appearance, which may or may not fit your pond aesthetic. Although marketed as “algae eaters,” these fish are omnivores, like koi and goldfish, so will require a complete pelleted diet for optimal health.

Caution Fish Options


“It’s all fun and games until somebody loses their head.” To start out, catfish can tolerate a wide range of outdoor temperatures, so they can be kept in fluctuating outdoor ponds. They are mostly easy going, until they’re not. They are easily seduced to eating small fish and we have seen them bite fish in half larger than themselves. We strongly caution against keeping catfish with fish who cannot defend themselves, like koi and goldfish. The catfish’s diet is similar to koi and goldfish, so they can share… nicely.



Yes, the kind that makes caviar. Some pond owners like the look of these prehistoric fish thrown in the mix. However, the biggest issue with sturgeon is temperature. They like it cold! Too warm for them is in the mid to upper 60s F (>18C). If you have a nice shady pond, they will do okay. But just like their koi friends, sturgeon can grow VERY BIG!!

Never in Ponds


You want an algae eater? There aren’t any good ones for outdoor ponds. Grab that rake and get to work! Plecostomous spp., commonly known as plecos, are tropical fish and therefore, not suited to outdoor ponds. Many owners will throw some in and assume the can’t see them due to their coloration. Sorry folks, but they’re dead. Keep them in an indoor heated tank!


Fancy Goldfish

For those of you who haven’t heard my rant against fancy goldfish, don’t make their lives harder by expecting them to swim around a pond. I’ve only seen this work ONCE and it was a tiny, heated outdoor pond. Their poor little smashed bodies and long fins makes it hard for them to swim in general. Don’t make them swim multiple football fields or expect to easily evade predators in a pond.

Any Tropical Fish

Tropical = heated. If you want to have a heated, outdoor pond, move somewhere tropical. Tiny, bright fish make great predator snacks!

Fish You Found in the River

No, no, just no! Wild caught fish do not do well in captivity unless you have a giant system, endless filtration and a well established trophic pyramid i.e. a public aquarium. Yes, it’s a fun “experiment” for kids in the summer, but don’t do that to your wild fish. Wild fish are swimming with disease and parasites that a wild environment allows them to cope with. Putting them in an artificial system is just setting them up for death. If you mix them with captive fish, you are condemning them too.


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