Best Coldwater Fishes For Aquarium Without Heater

Coldwater aquarium fish is easy to achieve at home as it is reasonably suitable for room temperature. Keeping cold-water aquarium fish makes heater out of the question since these are the fish that don’t need a heater. An indoor cold-water fish tank typically maintains a temperature of about 18-22 degrees which is considered temperate. With the growing unstable temperature of the planet, fish are gradually learning to adapt to their ever-changing environment.

Many tropical fish species can now survive and thrive in cold freshwater. Cold freshwater aquarium fish are usually a good fit for beginners as it doesn’t require much maintenance. A whole class of tropical coldwater fish can live in the cold water at a room’s temperature. Most tropical fish species prefer to live in cooler water temperatures. Coldwater aquarium fish species prefer water typically around or below 68° Fahrenheit.

15 Best Coldwater Aquarium Fishes (Don’t Need Heater)

Most freshwater fish are used to tropical temperatures, but a whole class of unheated aquarium fish species like cold water and live at room temperature.

Here are the fifteen best cold-water fish types that you can keep in your heater-free aquarium.

1. Sunset Variatus Platy

The Platy is amusing, pleasant, and peaceful freshwater fish that’s both strong and active. It’s also tiny, pretty, and an excellent fish for hobbyists of any level.

It’s one of the most popular and favorite in the fishkeeping industry. These fish are comparatively easy to care for and remain happy in cooler water. Their unique color combination gives a soothing view to fish lovers.

They are available in a wide variety of colors and patterns. They are easy to breed. The main features of this species are as under:

  • Maximum Size: 2.5 inches
  • Care Difficulty: Beginner-Intermediate
  • Minimum Tank Size: 15 gallons
  • Water Temperature: 72°F to 82°F

2. Glow Light Danio

It is another small freshwater pet fish that enjoys cool aquarium water. Glowlight Danio is easy to care for and handle as it adapts to water changes without any issue. These fish species are ideal for unheated tanks because they are highly tolerant to temperature variations.

The Glowlight Danio is an active fish in groups of 5 to 6. These tiny, slender fish survive best in a subtropical fish tank. Their radiant colors exhibit a soothing view to fish lovers. Being super active, these fish jump out of their home aquarium that needs to tackle wisely. These fish tend to happily school and interact with any peaceful species. Some salient features of this species are as under:

  • Maximum Size: 1 inch
  • Care Difficulty: Beginner-Intermediate
  • Minimum Tank Size: 10 – 15 gallons
  • Water Temperature: 68°F to 75°F

3. Odessa Barb

Odessa Barbs is another best choice for coldwater aquarium pet fish because of its hardy and pleasant nature.These species easily coexist with any aquarium mates and make the best match.

They are even easy to breed and form a peaceful community. These eye-catching Barbs can be kept in temperate and low tropical temperatures. They remain happy in heavily planted aquariums because of their curious nature. These fish have a stunning look exhibiting predominantly black color with black- spotted fins and a bright red stripe. Consider the following feature of Odessa Barb.

  • Maximum Size: 3 inches
  • Care Difficulty: Beginner
  • Minimum Tank Size: 30 gallons
  • Water Temperature: 70°F to 79°F

4. Bloodfin Tetra

Bloodfin Tetras are the gorgeously best choice for fish hobbyists. However, they are hardy to survive in cold water but shy at the time. Due to their aggressive nature, it is preferable to keep them in small groups.

They are readily available at pet fish stores, and you can quickly raise them in cold water aquariums without any difficulty. The specific characteristics are:

  • Maximum Size: 2 to 3 inches
  • Care difficulty: Easy/Beginner
  • Minimum tank size: 30 gallons
  • Water temperature: 60° to 70° F

5. Rainbow Shiner

The Rainbow Shiners are pretty hardy fantastic water fish primarily suitable for a community fish tank because of their peaceful nature. They come in vibrant purple and pink color with a mesmerizing look. They are a mix of color and metallic glimmer, genuinely reflecting their name.

These fish species add to the beauty of the water tank and make it a peaceful community. This fish type is rare, that’s why a bit costly. Their glowing color scheme is a must for your aquarium that shows your aesthetic sense.

  • Maximum Size: 3 inches
  • Care Difficulty: Beginner-Intermediate
  • Minimum Tank Size: 20 gallons
  • Water Temperature: 55°F to 75°F

6. Endler’s Livebearer

Endler’s Livebearer is a fantastic small fish having unique colors and fin shapes. They are tough enough to bear water at room temperature. They mix well with many of the fish on this list and are pretty peaceful to adopt. They are not only easy to care for but have pleasing as well.

These fish are very generous, chilly, and friendly. Any aquarist can adopt it as a pet fish best for cold water. Being small, they are vulnerable to a community tank, so keeping them in a separate tank is best.

  • Maximum Size: 2 inches
  • Care Difficulty: Beginner
  • Minimum Tank Size: 20 gallons
  • Water Temperature: 72° – 74° F

7. Fancy Gold Fish

Fancy Gold Fish is one of the best choices for home aquariums since their natural temperature requirements are low. These fish species are the best for beginners. Their happy, playful, and interactive nature pleases the aquarists. You can get them in a variety of pleasing colors, shapes, and sizes.

The presence of Fancy Gold Fish gives a glamorous look to the aquarium. They are very interactive and competitive eaters.

  • Maximum Size: Species-dependant
  • Care Difficulty: Beginner-Intermediate
  • Minimum Tank Size: Species dependant
  • Water Temperature: Species dependant

8. Hillstream Loach

Hillstream Loach does a fantastic job of keeping the tank clean as it munches diatoms and algae within no time. They enjoy cooler water, thus best matching your heater-less tank. This species is a unique one with a flat build that makes it prominent in the tank.

Their body structure helps them survive in fast-flowing waters. They are unusual fish that need highly oxygenated fast-flowing water.

  • Maximum Size: 2-3 inches
  • Care Difficulty: Intermediate-Expert
  • Minimum Tank Size: 50 gallons
  • Water Temperature: 68°F to 75°F

9. Paradise Fish

Paradise Fish, true to their name, have the most aesthetically-pleasing bright colors. Their beauty mesmerizes the aquarists. They are an exceptional choice for freshwater pet fish that appreciate a cold water aquarium. They can adapt to a vast range of temperatures. The charming hues of the Paradise Fish are a treat to the eyes.

One of the good things about Paradise Fish is that they can survive in cold and warm waters alike. They accept any food; therefore, the tank should have a good variety of plants.

Interestingly these fish can learn tricks that are uncommon with many aquarium fish.

  • Maximum Size: 2.5 inches
  • Care Difficulty: Beginner-Intermediate
  • Minimum Tank Size: 20 gallons
  • Water Temperature: 68°F to 82°F

10. Rosy Barb

Rosy Barb, a red-colored, active, and relatively peaceful fish, adds visual charm to any aquarium they’re kept in as pet fish. These fish are easy to handle and have an excellent ability to stay in cooler water.

When it comes to community, these species are active, friendly, and lively but aggressive.

They are one of the hardiest barbs that a beautiful and undemanding. They are readily available in fish stores and quite popular among aquarium hobbyists for many reasons. Their color will add charm to the tank’s beauty.

  • Maximum Size: 6 inches
  • Care Difficulty: Beginner-Intermediate
  • Minimum Tank Size: 30 gallons
  • Water Temperature: 64°F to 72°F

11. Red Shiner

Red Shiner is incredibly adaptable to low-temperature water as well as high-temperature water. They prefer cooler environments over warm surroundings, and that’s why experts consider them cold-water fish. They are pretty active and playful fish that eat both plants and flesh and sometimes algae. They don’t need extra care and can be handled easily in a heated fr aquarium.

These cold freshwater fish can be a good choice for your tank community. These species remain mainly in the middle and at the surface of the tank. Their males exhibit a unique color scheme during the breeding period, thus making themselves very attractive.

  • Maximum Size: 3 inches
  • Care Difficulty: Beginner-Intermediate
  • Minimum Tank Size: 20 gallons
  • Water Temperature: 59°F to 77°F

12. Rainbow Goodeid

Rainbow Goodeid is a beautiful fish but a bit pricy at the same time. However, it is hardy, low maintenance, easy to feed, and tolerant to a considerable range of temperatures.

Its patterns are unique in design and color. It is endangered, so before you adopt it, study about it thoroughly to manage it in your tank.

  • Maximum Size: 2 inches
  • Care Difficulty: Beginner-Intermediate
  • Minimum Tank Size: 20-30 gallons
  • Water Temperature: 67°F to 76°F

13. Rubber Lip Plecostomus

Rubber Lip Plecostomus belongs to a hardy Pleco variety. They grow to 7 inches long and need a bit larger tank. They are freshwater fish that enjoys rapid changes in water temperature.

It makes a terrific pet as they nibble the algae stick to the bottom of your aquarium. They are peaceful who tent to themselves without bothering others in a community tank.

  • Maximum Size: 7 inches
  • Care Difficulty: Beginner-Intermediate
  • Minimum Tank Size: 20-30 gallons
  • Water Temperature: 72°F to 78°F

14. Gold Barb

The gold-colored fish is trendy in the aquarium trade that is named Gold Barb. They reach up to 3 inches in length. They are peaceful and remain comfortable with other Gold Barbs.

It is suitable for beginners because of its hardy and tolerant nature. They are a good eater, and if they don’t, there is something wrong with the water.

  • Maximum Size: 3 inches
  • Care Difficulty: Beginner-Intermediate
  • Minimum Tank Size: 20 gallons
  • Water Temperature: 64°F to 75°F

15. American Flagfish

American Flagfish is one of the best algae-eating pet fish for maintaining cold, clean water in an aquarium with blazing beautiful colors.

They are generally peaceful and social fish species however they require a spacious tank. It is one of the few species that eat black beard algae and keep the tank clean.

  • Maximum Size: 2.2 inches
  • Care Difficulty: Beginner-Intermediate
  • Minimum Tank Size: 20 – 30 gallons
  • Water Temperature: 67°F to 75°F

Ease Of Coldwater Fish

When you consider having pet fish as your fishkeeping hobby, you should prefer cold water pet fish. There are several advantages to keeping freshwater pet fish. Coldwater fish are

  • cheaper
  • have a longer life span
  • easy to care
  • makes fewer algae
  • space saving
  • no mess

Concluding Thoughts

The selection of coldwater fish depends on the expertise of the aquarists. An experienced fish-keeper can tackle both subtropical and tropical fish in the same aquarium as they know how to maintain temperature balance.

A beginner is to understand from remembering to feed them to cleaning the tank, and they will learn the importance of caring for something to keep it alive

A cold water aquarium should be n interesting and colorful tank with a tasteful variety of plants and vegetation. There are many species to choose from for a heater-free tank, but all you need is to make a wise choice.

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Sophia Rosa
Sophia Rosa

Sophia is a professional marine author having expert knowledge and practical experience in fish, fishing in aquariums, aquarium plants, etc. She is passionate about helping other people by sharing her expert knowledge on fish & fish keeping.

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