Pond Fish: Best Species for Small and Large Backyard Ponds

Backyard ponds can be simple, stunning, and low-stress when you match species to space and climate. This guide compares the best pond fish for patio tubs and small ponds versus large koi ponds, with clear stocking rules, climate and overwintering notes, and plant/filtration tips. You'll also get a first-48-hours checklist for smooth introductions. Every recommended fish links to a care summary and shopping options.

The best pond fish for small backyard ponds include hardy goldfish (comet, sarasa, shubunkin), rosy red minnows, white clouds, and Japanese ricefish. For larger ponds, koi, golden orfe, and schools of hardier goldfish are excellent. When starting, use dechlorinated and filtered water, acclimate slowly, and stock lightly. For cold climates, a pond depth of 30-36 inches or more is a must for overwintering.

Small Ponds & Patio Tubs (≈50–600 gal)

Starting a pond is one of the most rewarding things you can do in your backyard. Maybe you're starting small with a preformed tub, or maybe you’ve dug out a nice little 500-gallon hole. Either way, the fish you choose are just as important as the pond itself. Our advice? Start with the hardiest fish you can find. It’s all about setting yourself up for success and avoiding a lot of headaches later on. Here are some great little pond fish that are perfect for smaller volumes.

Comet Goldfish (Carassius auratus)

This is probably the most popular pond fish in the world, and for good reason. They are tough as nails, active, and can handle a wide range of temperatures. Their bright colors, usually a classic orange, make them easy to spot zipping around. They’re a fantastic starting point for any new pond owner.

Temperament/Size: Peaceful, but can get up to 10-12 inches over time.
Temperature Range: 55–78 °F (13–26 °C).
Notes: Great for beginners, very hardy and forgiving.

Sarasa Comet

If you want the hardiness of a regular Comet but with a little more flair, a Sarasa Comet is your best bet. They have a beautiful red and white pattern that really stands out against the green of a pond. They are just as tough as their solid-colored cousins and a little school of them looks gorgeous swimming together.

Temperament/Size: Peaceful, can reach 10-12 inches.
Temperature Range: 55–78 °F (13–26 °C).
Notes: Their colors provide a great visual contrast, especially with plants.

Shubunkin Goldfish

The Shubunkin is another great Goldfish variety. It's a calico pattern, so each one looks a little different:a mix of orange, white, and black with a speckled look. They’re super hardy and, like other comets, they are very active swimmers. They add a bit of wild beauty to any pond.

Temperament/Size: Peaceful, grows to 10-12 inches.
Temperature Range: 55–78 °F (13–26 °C).
Notes: Each fish has a unique calico pattern; very pond-hardy.

White Cloud Mountain Minnow

If you live in a place with a cooler climate, the White Cloud is a perfect choice. They're a bit different from other minnows because they're very cold tolerant. They are peaceful and love to school together. A small group of these guys is the perfect way to get started with a patio tub pond.

Temperament/Size: Peaceful, stays around 2 inches.
Temperature Range: 50–72 °F (10–22 °C).
Notes: A real favorite for patio tubs in cooler regions.

Large Ponds (≈1,000+ gal)

Once you get into a larger pond, you can start thinking about some truly impressive fish. These are the showstoppers, the fish that make a pond the centerpiece of a whole yard. One classic pick is Koi, but there are a few other options that look great too.

Koi (Cyprinus rubrofuscus)

Koi are the kings of the pond. They are long-lived and can grow to be massive. The colors and patterns are amazing, and each one is completely unique. A clear, well-maintained pond with a few big Koi is a sight to behold.

Temperament/Size: Peaceful, but can reach 2-3 feet long.
Temperature Range: 39–75 °F (4–24 °C).
Notes: They need pristine water and lots of space.

Golden Orfe (Leuciscus idus)

These are beautiful, sleek, fast-moving fish. They love to school together and are a joy to watch from the surface. They have a brilliant golden color that really pops. They do best in a high-oxygen pond, so you’ll want to make sure your aeration is top-notch.

Temperament/Size: Peaceful and fast, can grow to about 12-16 inches.
Temperature Range: 50–78 °F (10–26 °C).
Notes: Excellent jumpers, so a lid might be needed. They thrive in a high-oxygen environment.

Large Goldfish (Comet/Shubunkin/Sarasa)

Yes, the same goldfish from the small pond section work great here, too. The difference is that in a big pond, you can have a massive school of them. They are a bit easier to keep than Koi, and a group of them looks stunning. They are also great with plants.

Temperament/Size: Peaceful, grows to 10-12 inches.
Temperature Range: 55–78 °F (13–26 °C).
Notes: Easier to care for than Koi, and a large group provides tons of color.

Stocking Rule (large ponds): For Koi, a good rule is to plan on 200-250 gallons of water per fish. For goldfish, it’s closer to 20-50 gallons per fish. You also need to have a seriously good filtration system: we're talking big biofilters and a UV clarifier to keep the water clear.

Climate & Overwintering (Depth, Oxygen, Ice)

This is a big one. A lot of people think their fish will just die in the winter, but it's not true! You just have to plan for it.

Cold Climates: Your pond needs a deep spot, at least 30-36 inches deep. This creates an area at the bottom where the water won’t freeze, and the fish can stay in a state of near-dormancy. The most important thing is to keep a hole in the ice with a pond de-icer or an air stone. This lets gases escape and keeps the oxygen flowing. Without it, the gases can build up and kill your fish.
Hot Climates: When it gets really hot, you need to provide plenty of shade. Water lilies are perfect for this, but a pergola or a shaded area works great too. You'll also want to make sure your aeration is running strong to keep oxygen levels up. It's a good idea to avoid feeding heavily in the middle of a heat wave.
pH & Hardness: No matter where you live, you want to keep your pH stable, somewhere between 7.0 and 8.0 is perfect for most pond fish. Having a stable carbonate hardness (KH) is key for keeping your pH from swinging all over the place.

Plants, Filtration & Clear Water

These three things work together to make a clean, healthy pond.

Filtration: A good filter should have two parts: mechanical and biological. Mechanical filtration is just the physical removal of big stuff like leaves and fish waste. Biological filtration is the most important part, that's where the good bacteria live and do their work. You should aim for your filter to turn over the pond water about 1-2 times per hour.
Plants: We love pond plants. Water lilies are great for shade and look beautiful. Marginals like irises or pickerel plants suck up a lot of the nutrients that algae would otherwise use. Some pond owners even use oxygenating plants like hornwort (check if it’s legal in your area first).
Algae Control: The best way to deal with algae is to prevent it. Don't overstock your pond and don't overfeed your fish. If you get a green water problem, a UV clarifier is your best friend.

Feeding & Care by Season

Spring/Fall: Feed a low-protein, wheat-germ-based food. Only feed your fish when the water temperature is above 50°F (10°C).
Summer: This is when your fish are most active and growing. You can feed a higher-protein food. It's better to feed a few small meals throughout the day rather than one big one.
Winter: If your pond freezes over, do not feed your fish at all when the water temperature is below 50°F (10°C). They are in a state of dormancy and can't digest food.

First 48 Hours After Adding Pond Fish (Checklist)

Getting new fish is exciting, but the first two days are the most critical. Here’s what you should do to make sure everything goes smoothly.

Before fish arrive

Make sure your water is dechlorinated and your filter has been running for at least 48-72 hours.
Confirm that your ammonia and nitrite readings are at zero.
Have some shade or plant cover in the pond for the new fish.

Hour 0–2 — Acclimation

Dim the lights around the pond.
Float the bag with the new fish in the water for 15-20 minutes to equalize the temperature.
Slowly mix small amounts of your pond water into the bag over 30-45 minutes.
Use a net to gently transfer the fish into the pond. Don't pour the bag water into your pond!

Hour 2–24

Keep the aeration high.
Don’t feed them a lot. A tiny pinch of food is all they need.
Test your ammonia and nitrite levels. If they rise above 0.25 ppm, do a partial water change.

Hour 24–48

Repeat your water tests.
Feed lightly once or twice a day.
Keep an eye on the fish. Make sure they aren’t gasping at the surface or rubbing against rocks.

Legal & Ecological Notes (important)

This is a big one: You have to check your local regulations before you get any fish. Some species, like Mosquitofish, are invasive in some areas and are illegal to own.

And for the love of all that is aquatic, never, ever release your pond fish or plants into a local waterway. It can be a disaster for the local ecosystem.

FAQs

What are the best pond fish for small ponds?

The best pond fish for small backyard ponds are hardy goldfish, including comet, sarasa, and shubunkin varieties. They are small, tough, and make a great choice for beginners.

How many pond fish can I keep?

You should always stock lightly. A good rule of thumb is 20-50 gallons per goldfish and 200-250+ gallons per koi. Start with fewer fish than you think you need, and you can always add more later.

Do I need filtration and aeration?

Yes, you absolutely need both. Filtration keeps the water clean, and aeration keeps oxygen levels high. Together, they create a healthy environment for your fish to live in.

How do I overwinter pond fish in cold climates?

You need to make sure your pond has a deep spot (at least 30-36 inches) that won't freeze solid. Keep a hole in the ice with a de-icer or aerator so that toxic gases can escape. Do not feed your fish when the water is below 50°F (10°C).

What plants work best with pond fish?

Water lilies are great for shade, and marginal plants like irises help absorb extra nutrients. Just be sure to check that the plants you choose are not considered invasive in your area.

How should I feed pond fish through the seasons?

In spring and fall, use a wheat-germ-based food. In summer, you can use a higher-protein food for growth. In winter, do not feed your fish at all when the water is below 50°F (10°C). They are in a state of dormancy and won't digest the food.