37 Best Cold Water Aquarium Fish (No Heater) for 2022

Cold Water Aquarium Fish

Though many pet owners seem to primarily favor the furrier species, fishkeeping is starting to become very popular in the world of animal companions, with people opting for schools of scaly pals to grace their fish tanks.

Keeping fish as pets is a wonderful hobby for many people, who take enjoyment from caring for their fishy friends and watching their antics within the aquarium. And while tropical fish are increasingly popular, what sorts of fish can you fill your cold water tank with?

After checking out our roundup of the best cold water aquarium fish that can happily live in cooler conditions without a tank heater, adding fish to your indoor aquarium will be a breeze after you decide on which species appeal most to you.

From large tank schools to nano tank swimmers, there are many options for cold water aquarium fish to live in your aquarium. Read on for a list of 30 of our top fishy picks!

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1. Asian Stone Catfish

Typical Fish Size: 1.5 inches

Care Difficulty Level: Intermediate

Minimum Tank Size: 10 gallons

Ideal Water Temperature: 60°F to 75°F

A fish with an interesting appearance, the Asian Stone Catfish is a small fish that enjoys being kept in groups of six or more. They are neutral in temperament, making them a great addition to a tank with other fish.

Enjoy their geometric designs, wide eyes, and facial feathering that is reminiscent of a clear, open umbrella as they swim peacefully around the tank.

2. Bloodfin Tetra

Typical Fish Size: 2 to 3 inches

Care Difficulty Level: Easy

Minimum Tank Size: 30 gallons

Ideal Water Temperature: 60°F to 70°F

These hardy little fish are easy to care for, making them a great addition for any beginning fishkeepers. They are also one of the most commonly available in a variety of pet shops and aquatic suppliers, along with other tetra types.

Bloodfin Tetras tend to be quite shy fish, and while they can be timid around other species in a community aquarium, they flourish when living in a school with at least six others. Make sure to give them hides and plants to tuck themselves away in.

3. Bristlenose Pleco

Typical Fish Size: 3 to 5 inches

Care Difficulty Level: Easy

Minimum Tank Size: 20 gallons

Ideal Water Temperature: 75°F to 82°F

Commonly added to a tank as algae eaters, the Bristlenose Pleco is a great fish in its own right. They are a very popular fish that is related to the larger plecostomus catfish found in the wild.

Fishkeepers enjoy their dinosaur-like appearance and quirky personality. Plus, these fish get along well with others, so adding one or two to your community tank will not cause problems.

4. Buenos Aires Tetra

Typical Fish Size: 2 to 3 inches

Care Difficulty Level: Easy

Minimum Tank Size: 30 gallons

Ideal Water Temperature: 64°F to 82°F

A favorite among fishkeepers of any level, tetras are an easy fish found in most fish stores. However, the Buenos Aires tetra is a particularly active and flashy addition to any coldwater aquarium. They are hardy and have unique personalities.

Happiest in a school of eight or more fish, you can enjoy the shiny, mesmerizing display as they swim. These tetras also can be found in albino variants, which can add an interesting dimension to your tank.

5. Celestial Pearl Danio

Typical Fish Size: 2 inches

Care Difficulty Level: Easy

Minimum Tank Size: 10 gallons or a nano tank

Ideal Water Temperature: 73°F to 79°F

Hailing originally from Thailand and Sumatra, the Celestial Pearl Danio is an easy to care for, hardy fish. Their appearance is unique—a slender body with a forked tail, paired barbels, and an overall pearlescent sheen.

These fish like to have plenty of hiding material within the tank, and are happiest when in a school with other danios. With a reputation of having quirky personalities and big appetites, they get along well in a community tank.

6. Clown Killifish

Typical Fish Size: 1 inch

Care Difficulty Level: Easy

Minimum Tank Size: 10 gallons or a nano tank

Ideal Water Temperature: 68°F to 79°F

A spritely little fish with a big personality and a penchant for jumping, your tank life will be invigorated with the addition of the Clown Killifish. They are a peaceful breed that gets along with all other fish, preferring to keep to the top of the tank and out of the way.

With that being said, ensure your tank lid is fitted tightly, as Clown Killifish enjoy aerial jumping displays out of the water. You don’t want your fish jumping for joy and landing on the floor!

7. Dojo Loach

Typical Fish Size: 6 to 10 inches

Care Difficulty Level: Easy

Minimum Tank Size: 30 to 40 gallons

Ideal Water Temperature: 60°F to 80°F

For anyone who thinks that catfish are adorable, this is the fish for you. Dojo Loaches are long, cylindrical creatures with tiny, stumpy fins, primarily found in gold and silver varieties with black spots.

For anyone keeping Dojo Loaches, make sure that you keep them in a relatively large school and have sand substrate on the bottom of the tank instead of gravel. These fish like to burrow, and any hard bottom material will harm their bodies.

8. Empire Gudgeon

Typical Fish Size: Up to 4.7 inches

Care Difficulty Level: Intermediate

Minimum Tank Size: 30 gallons

Ideal Water Temperature: 72°F to 82°F

Hailing from Papua New Guinea and Australia, this fish has a captivating appearance. With red and tan markings and striking white, black, and orange edges to its bright red fins, it’s a delightful addition to your tank.

Widely regarded as one of the most interesting fish to watch and keep, Empire Gudgeons are primarily wild-caught fish that retain their original habits. They do require frozen shrimp, worms, and larvae to mimic a natural prey diet.

9. Endler’s Livebearer

Typical Fish Size: 1 to 1.8 inches

Care Difficulty Level: Intermediate

Minimum Tank Size: 10 gallons or a nano tank

Ideal Water Temperature: 75°F to 81°F

At one time, this fish was thought to have been brought to extinction, due to overfishing in its native area of Northeastern Venezuela. But thanks to their ability to breed at a fast rate, Endler’s Livebearer are alive and well, and a great addition to your fish tank.

Livebearers like to swim in medium-sized schools, and they mix well with other types of fish, being peaceful in temperament and easy to care for.

10. Fancy Goldfish

Typical Fish Size: 2 to 4 inches

Care Difficulty Level: Easy

Minimum Tank Size: 50 gallons

Ideal Water Temperature: 60°F to 80°F

Though they are one of the most common choices for a cold water tank, this doesn’t take away from the Fancy Goldfish’s elegant and adorable contribution to your aquarium setup.

With a variety of colors, sizes, and shapes, goldfish are very social individuals who need to be kept either in small groups or pairs. They are easy to look after, but with a large waste amount, you need to make sure your tank is fitted with a good filter to keep the water clean.

11. Galaxy Rasbora

Typical Fish Size: Up to 1 inch

Care Difficulty Level: Easy

Minimum Tank Size: At least 10 gallons or a larger nano tank

Ideal Water Temperature: 65°F to 75°F

These small, schooling fish sport gorgeous colors that are reminiscent of a small trout, and are ideal for small, planted cold water tanks. While they can be shy, Galaxy Rasbora tend to come out of their shells quickly when living in a community tank with other fish.

They are highly communal and quite intelligent, meaning that you need to have at least five others in a school— and because they are very small, you could even fit eight to ten comfortably in your tank.

12. Gold Barb

Typical Fish Size: 2 to 3 inches

Care Difficulty Level: Easy

Minimum Tank Size: 20 to 30 gallons

Ideal Water Temperature: 65°F to 75°F

A newly popular type of cold water aquarium fish, Gold Barbs are a gorgeous aquarium addition. Their yellow-gold coloring is only amplified when swimming with a school of other Gold Barbs, as they prefer to be housed with six to eight friends.

They fit well in a communal tank, but be aware that Gold Barbs tend to be a bit nippy with others.

13. Guppy

Typical Fish Size: Up to 2.5 inches

Care Difficulty Level: Easy

Minimum Tank Size: 30 gallons

Ideal Water Temperature: 60°F to 70°F

A perennial favorite among fishkeepers, Guppies are hardy and easy to keep. They also come in a range of colors and styles, so your tank can have a virtual rainbow of Guppies—in fact, there are over 55 varieties of Fancy Guppies available!

With elongated bodies and forked tails, Guppies are mischievous fish who like to swim in a medium-sized school and hide in the aquarium plants. They also get along well with other kinds of fish.

14. Hillstream Loach

Typical Fish Size: Up to 3 inches

Care Difficulty Level: Easy

Minimum Tank Size: 30 gallons

Ideal Water Temperature: 69°F and above.

A fish that is comfortable in the higher range of cold water temperatures, the Hillstream Loach is a unique and adorable addition to your tank. They originally hail from the waters of South and East Asia, and as algae eaters they can help keep your aquarium clean.

They primarily like to rest on the substrate and flat surfaces of your tank, and are amenable to sharing the water with any other fish types you might have.

15. Least Killifish

Typical Fish Size: From 0.75 to 1.5 inches

Care Difficulty Level: Easy

Minimum Tank Size: 10 gallons or a nano tank

Ideal Water Temperature: 65°F to 80°F

These tiny, easily maintained fish are a very tolerant and adaptable species, able to withstand slight fluctuations in temperature. Least Killifish are shy and prefer to hide in plant life or within aquarium structures, rather than go swim and mingle with other species.

The Least Killifish is also the world’s smallest fish that bears live young, and if your tank conditions are just right, they can produce many baby fry at a time.

16. Medaka Ricefish

Typical Fish Size: 1.5 inches

Care Difficulty Level: Easy

Minimum Tank Size: 10 gallons or a nano tank

Ideal Water Temperature: 64°F to 75°F

While Ricefish can live in conditions colder than even 50°F, they are perfectly happy to exist in a more temperate cold water range along with other fish. They prefer tank water that is slow-moving, and like to group with others of their kind.

Medaka Ricefish are a tranquil and friendly breed, so they can be added to a tank with other types of fish. Just make sure that all the other fish in the tank are about the same size as your Ricefish, as they are so peaceful that they tend to get attacked by larger fish.

17. Mosquito Fish

Typical Fish Size: 1 inch

Care Difficulty Level: Easy

Minimum Tank Size: 10 gallons or a nano tank

Ideal Water Temperature: 40°F to 80°F

Though sometimes overlooked for a more colorful species, Mosquito Fish are a wonderful addition to your cold water aquarium. They have a bright silver coloring and have a reputation for being lively and active.

Not only can these fish be kept in your indoor tank, but if you have an outdoor pond, Mosquito Fish can even thrive in those conditions—and, true to their name, help keep the native mosquito population in check.

18. Odessa Barb

Typical Fish Size: 2 to 3 inches

Care Difficulty Level: Easy

Minimum Tank Size: 30 gallons

Ideal Water Temperature: 60°F to 70°F

An eye-catching fish that likes to swim in a large group with others of its kind, the Odessa Barb needs at least five others to be happy in your tank. They sport a red stripe right down the middle of their sides, with black-ringed scales and spotted fins.

Though they mix well with fish of comparable sizes to themselves, Odessa Barbs can get nippy if you have smaller fish in the tank.

19. One-Sided Livebearer

Typical Fish Size: 1 inch

Care Difficulty Level: Easy

Minimum Tank Size: 10 gallons or a nano tank

Ideal Water Temperature: 60°F to 73°F

These hardy fish are eye-catching, to say the least. They have shimmering sides that can look like a series of holograms when swimming in a school, as they like to have friends in the same tank.

One-Sided Livebearers are very active fish that can provide you with hours of entertainment when watching their antics, but are also very shy and get spooked easily. Make sure to add plenty of hides and plants for them to take refuge in.

20. Panda Cory

Typical Fish Size: 2 to 3 inches

Care Difficulty Level: Easy

Minimum Tank Size: 10 gallons or a nano tank

Ideal Water Temperature: 65°F to 80°F

An adorable type of catfish that thrives in a cold water tank, the Pandy Cory is a lovely inhabitant to have in your communal tank. They are a schooling fish that requires about six other friends to group with.

But once the Panda Cory is comfortable in its environment and shoal, you get to see its quirky little personality come out, and they can be quite active. They mix placidly with other fish of a similar size, but be aware of the little spines that run along the side of their bodies.

21. Paradise Fish

Typical Fish Size: 4 inches

Care Difficulty Level: Intermediate

Minimum Tank Size: 30 gallons

Ideal Water Temperature: 60°F to 85°F

An ethereal-looking fish with long, floating fins and gorgeous coloring, Paradise fish are a species of gourami that come in bright colors. However, these fish are more difficult to handle than some of the other species on this list, so they require a more experienced keeper.

These fish are known for having an aggressive nature, but can still cohabitate with other species, as long as the others are placid in temperament and are able to put up with the more feisty Paradise fish.

22. Pygmy Sunfish

Typical Fish Size: From 1.5 to 2 inches

Care Difficulty Level: Intermediate

Minimum Tank Size: 5 to 10 gallons or a nano tank

Ideal Water Temperature: 60°F to 75°F

A lovely fish with metallic sheens and sleek forms, Pygmy Sunfish are perfect for cold water aquarium tanks, and can even thrive in outdoor ponds and water features. These fish are available in a variety of colors, including blue, gold, and teal.

However, they are one of the shyer species of fish, and do not flourish in a community tank setting. They much prefer to exist in a single-species setting, with a school of other Pygmy Sunfish for company. They are also picky eaters, which requires some skill on the part of the keeper to keep them healthy.

23. Rainbow Goodeid

Typical Fish Size: 2 to 3 inches

Care Difficulty Level: Easy

Minimum Tank Size: 30 gallons

Ideal Water Temperature: 60°F to 70°F

This is an unusual-looking fish that can make a great addition to your cold water aquarium setup. The Rainbow Goodeid resembles a pufferfish, but is not related, simply sharing the smiling expression and plump cheeks.

They are very easy to care for, and are tolerant to temperature fluctuations and a variety of tank conditions. However, because these fish are not commonly offered for sale in pet or fish stores, it is not definitively known if they can safely cohabitate with other species of fish.

24. Rainbow Shiner

Typical Fish Size: 3 to 3.5 inches

Care Difficulty Level: Easy

Minimum Tank Size: 30 gallons

Ideal Water Temperature: 50°F to 72°F, but happiest in the range of mid-60°F

This brilliantly colored fish lends a stunning vibrancy to your tank, with purple and pink tones that sparkle and are true to its name. The Rainbow Shiner is native to the United States, and is a great option for fishkeepers looking for low-maintenance inhabitants for their cold water tank.

They like to be kept company by others of their species, so you should have at least six of them in a tank. While they do mix well with other fish, they tend to steal the show with their glittering shoal displays.

25. Rosy Barb

Typical Fish Size: Up to 6 inches

Care Difficulty Level: Easy

Minimum Tank Size: 30 gallons

Ideal Water Temperature: 60°F to 70°F

A cheerful fish that originates from the waters of Bangladesh and Afghanistan, the Rosy Barb is the hardiest of the wider barb family. These fish will thrive in cold water aquariums, or even a tropical tank that remains on the lower end of the temperature range.

They are very active and lively, and need to be kept in a small school of four to six other barbs. As for temperament, Rosy Barbs are placid and peaceful, able to live easily in a community tank setting.

26. Rosy Red Minnow

Typical Fish Size: 2 to 3 inches

Care Difficulty Level: Easy

Minimum Tank Size: 30 gallons

Ideal Water Temperature: 60°F to 70°F

These fish are sometimes sold as feeder fish, with a low price tag to match, but Rosy Red Minnows actually make a great addition to your aquarium! They are tough, attractive fish that can survive temperature fluctuations and changes in location.

They come in a variety of colors and like to swim in a school with at least six Rosy Red Minnows in total, as they are a very social and inquisitive species.

27. Sunset Variatus Platy

Typical Fish Size: 2 to 3 inches

Care Difficulty Level: Easy

Minimum Tank Size: 30 gallons

Ideal Water Temperature: 61°F to 75°F

Not only are these fish available in a wide range of colors and patterns, but the Sunset Variatus Platy are also lively fish that get along wonderfully with other species. They are hardy and easy to breed, meaning that you will never have a shortage of these colorful, inquisitive individuals!

They love to exist as part of a large group within your aquarium, and enjoy having plants, caves, and other structures within the tank to explore and hide in. In return, you will get hours of entertainment from watching their antics.

28. Two-Spotted Barb

Typical Fish Size: 2 to 3 inches

Care Difficulty Level: Easy

Minimum Tank Size: 30 gallons

Ideal Water Temperature: 60°F to 70°F

Another unusual type of fish, the Two-Spotted Barb is difficult to find at most pet stores, as wild populations are under threat in their native Pakistan, India, and Nepal. However, if you can get your hands on one, this fish is a brightly colored and friendly addition to your aquarium.

They are lively and friendly fish, and require companions within the tank as they like to play with each other—perfect for a communal aquarium setting with other species.

29. White Cloud Mountain Minnow

Typical Fish Size: 1.5 inches

Care Difficulty Level: Easy

Minimum Tank Size: 10 gallons or a nano tank

Ideal Water Temperature: 60°F to 70°F

One of the easiest types of fish to care for in a tank, the White Cloud Mountain Minnow is a vibrant and active addition to your tank. They tend to have endearing personalities and like to zip around the tank at high speeds, showing off their red, gray, and gold colorations.

Though the original population is dwindling in China, where they are native, these minnows breed very easily in captivity. This means that you may find yourself with some fish fry in your tank! They live happily with other fish species, so long as they aren’t the smallest fish in the tank.

30. Zebra Danio

Typical Fish Size: From 0.5 to 1.5 inches

Care Difficulty Level: Easy

Minimum Tank Size: 10 gallons or a nano tank

Ideal Water Temperature: 64°F to 75°F

A tiny fish that is bursting with personality, the Zebra Danio is a favored part of many fishkeepers’ tanks. Originally from South Asia and incredibly easy to care for in captivity, you can find these adorable little fish in most pet stores or fish suppliers.

They like to get into mischief and are incredibly fast and active, so make sure your tank has plenty of structures, plants, and surfaces for them to explore in a school of at least three other danios. Plus, Zebra Danios can coexist with other fish in the tank, making them a great option for your cold water aquarium.

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FAQ

Do you have any burning questions about having cold water aquarium fish? Read on for further information on the practice of fishkeeping that will help you outfit and fill your cold water aquarium swimmingly well.

What Fish Can Live In Cold Water Tank?

Luckily for anyone who wants to delve into keeping fish, a cold water tank setup is ideal for a wide variety of fish species. And because cold water fish are typically easier to care for than their tropical brethren, they are a favorite.

Fish for cold water tanks include many popular types such as danios, livebearers, shiners, guppies, and barbs, among the others discussed in this article.

Is Cold Water Good For Aquarium Fish?

The short answer to this is yes—however, cold water is primarily good for cold water species of fish. If the species naturally prefer temperatures below 70°F to 75°F, they are typically considered cold water fish and thrive in those conditions.

Though cold water is good for aquariums that house cold water fish, the water should never approach frigid temperatures. If it does, then even the cold water auqarium fish in your aquarium will stop eating and could die with water temperatures that are near to freezing.

Can Cold Water Fish Live In Tropical Tank?

Technically speaking, cold water fish can survive in a tropical tank, but it is generally not advised. The warm water conditions of a tropical tank is not ideal for a cold water fish’s digestive tract or metabolic system, so living there will impact their health and shorten their lifespan considerably.

Fish should always be kept at the temperature that is best for their particular species, whether that is cold water or tropical conditions.

How Long Till Tap Water Is Safe For Fish?

Because tap water contains chlorine, it is not immediately safe for use in a fish tank. Chlorine makes the water safe for people to consume, but is highly toxic for your fish. Tap water needs to rest for at least 24 hours for the chlorine to evaporate before adding it to your aquarium.

However, if your tap water contains higher levels of chlorine, it can take up to five days for the dechlorination process to complete. Use a strip test available from your local fish supply store to ascertain the chlorine levels in the water and make sure it’s safe to use.

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Final Thoughts

Among the range of pets available to people, fish are sometimes overlooked in favor of their furrier counterparts.

However, as fishkeepers and aquarium enthusiasts alike are well aware, having fish in your house not only provides a sense of companionship, but they also contain very unique and individual personalities.

And with most cold water aquarium fish being easy to keep and a joy to watch in their day-to-day lives, adding an aquarium filled with any of the previously mentioned species to your home can be a great choice.