Top 20 Best Cold Water Aquarium Fish (No Heater Needed)

Cold Water Fish

Cold water aquarium fish can be just as beautiful and fun as tropical fish. Fish that come from temperate waters do not usually need an aquarium heater to survive. The temperature of the surrounding environment is warm enough for them.

Many fish from cold climates are much healthier and more resilient than those from the tropics too.

If you want to keep a cold water tank then keep reading to find out the best 20 cold water fish to stock it with.

What is a Cold Water Aquarium Fish?

In the aquarium hobby cold water typically refers to a water temperature below 70°F.

Most cold water fish thrive in temperatures between 60 and 65°F – this is considered room temperature in most environments. Cold water fish are fish that don’t need a heater.

The Dojo Loach and the White Cloud Mountain Minnow are two famous examples of cold water fish. These species come from high altitudes where the rivers and streams are chilled by crisp mountain air.

Other species can originate in tropical climates but are resilient enough to handle drops in water temperature. The Zebra Danio, for example, is a tropical fish that can survive in temperate waters. There are even some species that can survive in temperatures below 60°F, or can withstand winter temperatures by entering functional dormancy. The Koi fish is an example of one of these.

Because fish are ectotherms their body temperature matches the temperature outside.

They cannot generate their own body heat in these environments.

For this reason you do not want to place a fish in truly frigid waters. As a rule you should not attempt to keep any fish in temperatures below 50°F.

20 Best Cold Water Aquarium Fish

20. Japanese Rice Fish

Japanese Rice Fish

The Japanese Rice Fish is not a very common fish, but it is an excellent alternative to Tetras and Rasboras. Unlike tropical nano fish it can survive in water at 60°F. In the wild these fish are used to keep pests away from rice paddy gardens. These stark white fish look almost albino, except for their bright blue eyes. They are very active and excellent for bringing life to a thicket of underwater plants.

The only downside to these fish is the price tag. They are much more expensive than other nano fish and start at about $25 for a group of 6.

  • Size: 1.5 inches
  • Care Level: Easy
  • Tank Size: 10 gallons
  • Water Temperature: 60°F-75°F

19. Clown Killifish

Clown Killifish

Clown Killifish are one of the few freshwater Killifish that can live in cold water. Their suitable temperature range starts at 65°F. Unlike most Killifish that come from temporary bodies of water, Clown Killifish actually come from permanent bodies of water and can live for up to 5 years.

To keep them happy you must keep them in schools of 8 to 12. They will also need lots of live freshwater plants.

The Clown is one of the best Killifish for first time keepers and is a great introduction to the Killifish family.

  • Size: 1 inch
  • Care Level: Easy
  • Tank Size: 10 gallons
  • Water Temperature: 65°F-80°F

18. Chinese High Fin Banded Shark

Chinese High Fin Banded Shark

The Chinese High Fin Banded Shark can withstand a water temperature as low as 55°F.

They are best known for their high dorsal fin. The younger the fish is the taller the dorsal fin will be. As it gets older, it will eventually grow into its fin and even out.

You will need at least a 300 gallon pond to keep this monsterfish happy. They will grow up to 4 feet long and can be very difficult for beginners to keep. While you do not need to worry about a heater, you do need a powerful canister filter to handle the waste they produce.

  • Size: 2-4 feet
  • Care Level: Hard
  • Tank Size: 300 gallons
  • Water Temperature: 55°F-75°F

17. Gold Barb

Gold Barb

Gold Barbs can live in a tropical or a temperate setup. They can handle water temperatures between 65 and 75°F. Most barbs are known for fin nipping and bullying – like the Tiger Barb. Fortunately the Gold Barb is free of these undesirable traits.

Their vibrant gold color outshines even the Goldfish and looks mesmerizing when swimming in a school of 6 or more. Because they are peaceful they can be kept with small docile fish like Tetras and Danios.

  • Size: 3 inches
  • Care Level: Easy
  • Tank Size: 20 gallons
  • Water Temperature: 65°F-75°F

16. Paradise Gourami


You may be surprised to learn that this colorful tropical fish can live in cold water. The Paradise Gourami can live in water at 65°F.

This radiant looking fish comes in shades of peacock blue, green, red, and orange. They look absolutely stunning in a 20 to 30 gallon tank, that is decorated with Java Fern, Dwarf Hairgrass, and Hornwort. If you are keeping a Paradise Gourami for the first time then it is better to keep them in a single species tank. Their aggression can make it difficult to keep them in a community tank.

  • Size: 3 inches
  • Care Level: Intermediate
  • Tank Size: 20 gallons
  • Water Temperature: 65°F-82°F

15. Asian Stone Catfish

The Asian Stone Catfish is both a cold and warm water fish.

You can keep them in cold tanks with a temperature range of 60-74°F. Because of their appearance they are not very popular but they have found a small following among lovers of oddball fish. When looking at them from above their fins look just like moth wings.

They make excellent additions to fast moving river biotopes where they will blend in with stones and rocky substrate to create an authentic look. If you want to watch them feeding then you will have to wait until nightfall before they are active.

  • Size: 2 inches
  • Care Level: Easy
  • Tank Size: 10 gallons
  • Water Temperature: 60°F-74°F

14. Pearl Danio

Pearl Danio

You might have heard of the Celestial Pearl Danio before, but the Pearl Danio is a little different.

When the light hits the Pearl Danio it shines just like a cultured pearl. Pearl Danios can live in water temperatures from 64 to 72°F. They can live in warm or cold community tanks but prefer the temperature to be on the cooler side. They tend to have trouble breathing in warmer waters.

These stark white fish are very noticeable when paired with dark colored plants and decorations. They will stand out in a community full of other Danios, Tetras, Rasboras, or Corys. Pearl Danios are extremely active and fun to watch and may surprise you with their amazing jumping abilities.

  • Size: 2.5 inches
  • Care Level: Easy
  • Tank Size: 30 gallons
  • Water Temperature: 64°F-72°F

13. Pygmy Sunfish

A Sunfish is a very unusual pick for an aquarium, but the Pygmy Sunfish is just the right size for a 10 gallon tank. They can live in tropical or temperate environments starting at 50°F.

The Pygmy Sunfish is one of the most beautiful species in the Sunfish family. The males have iridescent blue dots which are used to attract mates. They can change colors based on their mood and the condition of their environment.

These fish are nano tank friendly and appreciate the cover of Hornwort, Cabomba, and other floating plants.

They make good tank mates too.

  • Size: 1.5 inches
  • Care Level: Easy
  • Tank Size: 10 gallons
  • Water Temperature: 50°F-82°F

12. Rosy Barb

Rosy Barb

Rosy Barbs are some of the most hardy Barbs around. These fish can easily handle changes in water temperature, shifts in parameters, and many of the common mistakes made by novice fishkeepers. They can live in water temperatures as low as 64°F.

You can find them in a beautiful bright pink color and they can grow up to 6 inches long. They can fit in a 20 gallon tank and should be kept in a school of at least 5. When decorating their aquarium you should pick out plants with strong roots and stems. Weaker plants may be eaten or uprooted. Java Ferns are one of the best plants for a Rosy Barb. You can also use floating or overhanging plants such as Hornwort and Duckweed.

Their water should be oxygenated by adding a bubble filter or a few air stones. Your Rosy Barbs will fit into any community setup as long as the community does not include slow moving and long finned fish.

They will get along well with other Barbs, short-finned Livebearers, and Tetras.

  • Size: 6 inches
  • Care Level: Easy
  • Tank Size: 20 gallons
  • Water Temperature: 64°F-77°F

11. White Cloud Mountain Minnow

White Cloud Mountain Minnow

White Cloud Mountain Minnows are among the most colorful fish you can keep in a temperate aquarium. These high-altitude fish are used to temperatures as low as 60°F.

You can find them in three different colors: silver, gold, and albino. A typical Mountain Minnow is silver with an icy blue stripe and bright orange fins. They must school in a group of at least 6, but prefer groups of 10 to 12. Mountain Minnows make wonderful community fish and thrive with Dojo Loaches, Bristlenose Plecos, and Zebra Danios. You should avoid keeping White Clouds with Goldfish as they tend to nip at their fins.

  • Size: 1.5 inches
  • Care Level: Easy
  • Tank Size: 10 gallons
  • Water Temperature: 60°F-72°F

10. Panda Cory


Most Corydoras Catfish are tropical fish and need a water temperature of at least 72°F. The Panda Cory, however, is just fine at a minimum temperature of 65°F.

They are named after their black and white pattern. Because of this pattern and their hardiness, they are one of the most popular Corys. During the day your Panda Corys will shelter behind rocks and under shelves and caves. They will come out at night to look for food.

This is a good bottom dweller for Goldfish tanks. They will help clean up everything from water fleas and small worms, to algae and detritus. In addition to warmer Goldfish tanks these docile Catfish can fit in with White Cloud Mountain Minnows, Zebra Danios, and Livebearers.

  • Size: 2-3 inches
  • Care Level: Easy
  • Tank Size: 10 gallons
  • Water Temperature: 65°F-77°F

9. Common Pleco

Common Pleco

Common Pleco are typically a tropical species, however in certain circumstances they can be kept in temperatures below 70°F.

The lowest water temperature should be about 68°F. If your room or pond can reach this temperature then you may not need a heater. The setup should experience warmer temperatures at times from seasonal variation or the temperature of the room. However, there should be no dramatic rises or drops. Other water parameters, such as pH and salinity, should be stable. Aim for a pH of about 7.0 and a water hardness up to 25 dGH.

If you follow these rules you can keep a Common Pleco in your cold water tank. They are excellent for keeping the substrate clean. Their speckled scale patterns will complement your rocks and gravel. While they are not the most active fish you can watch them feed once the sun goes down. They will eat absolutely anything that they can find so do not pair them with any small fish or invertebrates.

Just remember that the Common Pleco is more difficult to care for if you are keeping it in a temperate setup. You should have a fair amount of experience with the species before you attempt to do so.

  • Size: 10-24 inches
  • Care Level: Intermediate
  • Tank Size: 75 gallons
  • Water Temperature: 68°F-77°F

8. Dojo Loach

Dojo Loach

The Dojo Loach is one of the best bottom dwelling fish for temperate tanks. It can live in water temperatures as low as 50°F. This little fish is one of the very best tank mates for Goldfish or Mountain Minnows. While the Goldfish bring life to the middle of the tank, the Dojo Loach will draw attention to the bottom.

Dojo Loaches are sensitive to changes in the weather and can tell when it is going to rain or storm. Their barbels are used to sense vibrations in the substrate and changes in water chemistry. They will swim in an upright motion when bad weather is coming. You can keep them with any peaceful fish or invertebrates that can handle lower water temperatures.

  • Size: 6 inches
  • Care Level: Easy
  • Tank Size: 55 gallons
  • Water Temperature: 50°F-75°F

7. Zebra Danio

Zebra Danio

The Zebra Danio is a very popular community fish for tropical tanks. However, not many people know that it can also be kept in cooler waters (minimum 64°F).

This fish is beloved for its docile nature and iridescent blue stripes. When kept in groups they will add life to even the most boring aquascape. Zebra Danios can live alongside other Danio species, such as the Pearl. They can also be kept with Goldfish, Panda Corys, Platys, and Gold Barbs.

Just as a side note, you can also find glow-in-the-dark morphs known as GloFish. This effect is achieved by injecting the fish with a protein that allows it to glow. While these morphs may look interesting it is much better to stick to naturally colored Zebrafish.

  • Size: 2-3 inches
  • Care Level: Easy
  • Tank Size: 10 gallons
  • Water Temperature: 64°F-75°F

6. Platy Fish

Platy Fish

Platy fish are robust little livebearers that can handle a mix of water conditions. Although most are from tropical climates, there are some species that can handle water temperatures down to 68°F. These fish come in all sorts of lovely colors, including: red, yellow, orange, and black. Some varieties can be bi-colored or even tri-colored.

In temperate waters they are often chosen as background fish for Goldfish tanks. This can be a bit risky because of the Platys’ small size. These fish are much better suited in communities full of other nano fish, like Pearl and Zebra Danios, White Cloud Mountain Minnows, and Cory Catfish.

  • Size: 2-3 inches
  • Care Level: Easy
  • Tank Size: 10 gallons
  • Water Temperature: 68°F-77°F

5. Hillstream Loach

Hillstream Loach

The Hillstream Loach looks just like a miniature stingray. They are well adapted to water temperatures between 65 and 75°F.

You will find they spend all of their time sucking the algae off of substrate, rocks, and other surfaces. They are an excellent little algae cleaner for a river biotope. They also do much better in temperate conditions which makes them perfect for a cold water aquarium.

Hillstream Loaches are only 3 inches long but must be kept in at least a 55 gallon tank.

  • Size: 3 inches
  • Care Level: Hard
  • Tank Size: 55 gallons
  • Water Temperature: 65°F-75°F

4. Mosquitofish


The drab grey Mosquitofish is usually kept for one reason: to keep mosquitoes out of a garden pond. This United States native can handle temperatures from 50 to 80°F. Mosquitofish are livebearing fish like Platys, Swordtails, and Mollies. However, they are much less colorful and less exciting to look at.

These fish are well known for hunting mosquitoes and their larvae, which is why they are recommended for outdoor ponds. You can also keep them in a single species aquarium.

In an aquarium you should focus on creating an environment rather than a community. This voracious, competitive fish is not very compatible with anything else. It should be kept in a 10 gallon tank, with a light water flow and a few cold water plants such as Green Cabomba. However where possible it is recommended you keep them in a pond rather than a tank.

  • Size: 1.5-2.5 inches
  • Care Level: Intermediate
  • Tank Size: 10 gallons
  • Water Temperature: 50°F-80°F

3. Bristlenose Pleco

Plecostomus Bristlenose Close Up

The Bristlenose Pleco is a nano sized algae eater. They are much more resilient to lower water temperatures than other Plecos and can survive in temperatures down to 60°F.

Bristlenoses are best known for the strange bristles on their snout. These are used for attracting mates and communicating with each another. They are also known for eating algae. They will eat up the algae and detritus that accumulates at the bottom of the tank, and you will often spot them clinging to your aquarium glass.

Overall they are one of the very best Plecos for community tanks and can fit into small or large setups. They get along with Goldfish, Mountain Minnows, and Dojo Loaches in a low temperature tank.

  • Size: 3-5 inches
  • Care Level: Easy
  • Tank Size: 25 gallons
  • Water Temperature: 60°F-75°F

2. Koi

Types Of Koi

Without a doubt the Koi is the most popular fish for outdoor ponds. They are healthiest in water kept above 60°F, but they can survive even colder temperatures (50°F) as the seasons change. In total there are over 50 different breeds of Koi fish to choose from.

The red and white Kohaku is the most popular. Other breeds include the deep blue Asagi, the shining gold Ogon, and the black and white Shiro Utsuri. The most sought after Koi breeds can cost over $1000.

They are extremely docile but have very large appetites. For this reason they should be kept only with large fish, such as the Golden Orfe or the High Fin Banded Shark.

  • Size: 1-3 feet
  • Care Level: Intermediate
  • Tank Size: 200 gallons
  • Water Temperature: 50°F-80°F

1. Goldfish


Goldfish are one of the most famous cold water aquarium fish of all!

Because they can live in waters as cold as 60°F you do not need an aquarium heater.

Goldfish are active, inquisitive, and intelligent fish that come in many different breeds, including: fancy Fantails, elegant Veiltails, colorful Shubunkins, and many more.

These fish may start out small but many breeds can grow up to 10 inches long.

They can be kept inside or outside, and in ponds they will get along very well with Koi fish. They can live with other breeds of Goldfish and other medium sized fish with a peaceful temperament. Due to their voracious appetites they should not be kept with small fish or invertebrates.

In the right conditions these fish are extremely hardy and can live for up to a decade. The best conditions include oxygenated water and a mix of floating and rooted plants.

  • Size: 5-10 inches
  • Care Level: Easy
  • Tank Size: 50 gallons
  • Water Temperature: 60°F-72°F

Closing Thoughts

Cold water fish tanks are usually less expensive to run, and fish from these climates are often hardier and healthier than their tropical cousins.

With so many great cold water fish out there an aquarium heater is no longer needed for a diverse and beautiful biotope.

By far some of the most popular picks are: Goldfish, Koi, Bristlenose Plecos, Hillstream Loaches, and Dojo Loaches.

What is your favorite fish on our list?

Let us know in the comments section below…