Which Aquarium Fish Don't Need a Heater:

This guide is all about, to put it another way, which cold-water fish can live in your aquarium without a heater in cool climates


Image shows a happy man watching cold water fish in an aquarium.Just set up an aquarium and can't decide on the right fish? I know exactly how you feel because I've been there myself. After extensive research, I've found that many cold-water fish can live comfortably in your aquarium without a heater.

Eager to find out which ones they are? Keep reading!

(View our cold water fish video here: )

Key Takeaways

  • Cold-water fish such as the White Cloud Mountain MinnowCelestial Pearl DanioHillstream LoachEndler's Livebearer, and Cherry Shrimp can thrive in an aquarium without a heater.
  • When choosing cold-water fish for your tank, consider their temperature tolerance and compatibility with other fish.
  • Proper water quality maintenance is crucial for the health of cold-water fish in an unheated aquarium.
  • Setting up a cold-water aquarium without a heater requires proper tank size and filtration, maintaining consistent water temperature, and providing adequate hiding places and vegetation.


Cold-Water Fish That Can Thrive Without a Heater

There are several cold-water fish species that can thrive without a heater in your aquarium, including the White Cloud Mountain MinnowCelestial Pearl DanioHillstream LoachEndler's Livebearer, and Cherry Shrimp.

White Cloud Mountain Minnow

White Cloud Mountain MinnowAs a seasoned aquarium enthusiast, I swear by the White Cloud Mountain Minnow as one of the best coldwater fish for an unheated tank. Originating from subtropical and temperate regions, they champion endurance and can bear temperatures below 70°F.

These small yet striking candidates add a captivating visual element to your aquarium with their dazzling red-orange fins against pale silver bodies. Not only are they resilient in colder waters, but these minnows also coexist peacefully with other fish species, making them quite amicable roommates within the aquatic community.

The ease of care coupled with their ability to thrive without a heater makes White Cloud Mountain Minnows an excellent choice for both novices and experienced hobbyists alike!

Celestial Pearl Danio

Pearl DanioOne cold-water fish that can thrive without a heater in your aquarium is the Celestial Pearl Danio. These little beauties are known for their vibrant colors and peaceful nature, making them a popular choice among aquarium owners.

Celestial Pearl Danios are native to Southeast Asia and prefer cooler water temperatures between 64°F and 72°F.

These small fish have a maximum size of about an inch, which makes them suitable for smaller tanks or community setups. They do well in groups, so it's recommended to keep at least six individuals together.

Celestial Pearl Danios are also relatively easy to care for, as they adapt well to various water conditions. Providing them with plenty of hiding places and vegetation will help create a natural environment where they can feel secure.

In conclusion, if you're looking for a cold-water fish species that can add color and charm to your aquarium without the need for a heater, consider adding some Celestial Pearl Danios to your tank.

Hillstream Loach

Hillstream LoachOne cold-water fish species that can thrive in an aquarium without a heater is the Hillstream Loach. These unique and fascinating fish are known for their ability to tolerate cooler water temperatures, making them suitable for unheated tanks.

Hillstream Loaches have adapted to fast-flowing streams in their natural habitat, which means they prefer well-oxygenated water with plenty of movement. They also enjoy hiding spots created by rocks or driftwood, so make sure to provide these in your tank setup.

With their beautiful patterns and serene nature, Hillstream Loaches can add a touch of elegance to any cold-water aquarium.

Endler's Livebearer

Endlers LivebearerI absolutely love keeping Endler's Livebearers in my cold-water aquarium! These vibrant little fish are not only beautiful but also incredibly hardy and adaptable to various water conditions.

They can easily thrive without a heater, making them perfect for aquarium owners who prefer a low-maintenance setup. With their bright colors and active nature, Endler's Livebearers bring life and energy to any tank.

They are also known for their peaceful temperament, making them compatible with other community fish species. So if you're looking to add some lively and low-temperature-loving fish to your aquarium, definitely consider the delightful Endler's Livebearer!

Cherry Shrimp

Cherry ShrimpWhen it comes to cold-water fish that can live in your aquarium without a heater, Cherry Shrimp is definitely one species you should consider. These small and colorful shrimp are known for their hardiness and adaptability to various water conditions.

They can withstand temperatures as low as 60°F (15°C), making them perfect for unheated tanks. Cherry Shrimp also have the added benefit of being excellent cleaners, as they feed on algae and organic debris in the tank.

With their vibrant red coloration, they can add a pop of color to your aquarium while requiring minimal maintenance. So if you're looking for an easy-to-care-for cold-water fish that doesn't require a heater, Cherry Shrimp may be just what you need!

Factors to Consider When Choosing Cold-Water Fish

When choosing cold-water fish for your aquarium, it's important to consider their temperature tolerance, compatibility with other fish, and water quality requirements.

Temperature tolerance

As an aquarium owner, it's important to consider the temperature tolerance of cold-water fish before adding them to your tank. Cold-water fish are adapted to thrive in cooler waters, typically below 70°F.

Unlike tropical fish, they don't require a heater to maintain their ideal environment. It's essential to choose species that can handle lower temperatures without compromising their health and well-being.

Some popular cold-water fish with excellent temperature tolerance include Endler's Livebearer, Celestial Pearl Danio, Rainbow Shiner, Hillstream Loach, Clown Killifish, Cherry Shrimp, Dojo LoachBarbs, and White Cloud Mountain Minnow.

Compatibility with other fish

One important factor to consider when choosing cold-water fish for your aquarium is their compatibility with other fish. It's crucial to select species that can coexist peacefully and won't pose a threat to each other.

Some cold-water fish are more peaceful and social, while others may be territorial or aggressive. It's essential to research the temperament and behavior of the fish you're interested in keeping and ensure they will get along well with your existing tank inhabitants.

Creating a harmonious community in your aquarium can help reduce stress among the fish and promote overall health and wellbeing.

Water quality requirements

Maintaining proper water quality is essential for the health and well-being of your cold-water fish. Coldwater fish have specific requirements when it comes to water parameters, so it's important to ensure that their habitat meets these needs.

Regular water testing and monitoring should be conducted to check levels such as pH, ammonia, nitrite, and nitrate. Keeping these levels in check will help prevent any potential issues and maintain a healthy environment for your fish.

It's also crucial to provide good filtration in your aquarium to keep the water clean and free from harmful substances. By maintaining optimal water quality, you'll create an ideal setting for your cold-water fish to thrive in without the need for a heater.

Setting up a Cold-Water Aquarium

To set up a cold-water aquarium, ensure you have a tank of appropriate size with proper filtration to maintain water quality.


Proper tank size and filtration

Choosing the right tank size and filtration system is crucial when setting up a cold-water aquarium without a heater. Depending on the species of fish you plan to keep, you'll need to provide adequate space for them to thrive.

Some cold-water fish, like goldfish, can grow quite large, so be sure to choose a tank size that allows for their growth. Additionally, investing in a good filtration system is essential for maintaining water quality in your aquarium.

Coldwater fish produce waste just like any other fish species, so proper filtration will help remove harmful toxins and keep your fish healthy. Remember to regularly clean and maintain your filter to ensure optimum performance and water clarity.

Maintaining consistent water temperature

To ensure the well-being of your cold-water fish, it's essential to maintain a consistent water temperature in your aquarium. Coldwater fish thrive best in cooler waters, so it's crucial to avoid drastic temperature fluctuations that could stress or harm them.

A good way to achieve this is by choosing a location for your aquarium that isn't exposed to direct sunlight or drafts, as these can cause rapid changes in water temperature. Additionally, investing in a reliable thermometer and adjusting your room temperature accordingly can help you maintain a stable environment for your cold-water fish.

Monitoring and maintaining the ideal tank water temperature for each specific species is key to creating a healthy living space tailored to their needs.

Providing adequate hiding places and vegetation

One important aspect of caring for coldwater fish in your aquarium without a heater is providing them with adequate hiding places and vegetation. This not only helps create a natural environment for the fish but also provides them with shelter and places to explore.

Adding driftwood, rocks, and plants such as Java moss or Anubias can create hiding spaces where fish can feel safe and secure. Having these features in your tank also helps mimic their natural habitat, promoting their overall well-being and reducing stress levels.

It's vital to ensure that the decorations are suitable for cold-water conditions and won't harm the fish or affect water quality. So consider adding some hiding places and greenery to enrich your coldwater aquarium setup!

Tips for Caring for Cold-Water Fish

Regular water testing and monitoring helps ensure that your cold-water fish are in a healthy environment. Maintaining proper water parameters is essential for their well-being. Want to know more tips on how to care for your cold-water fish? Keep reading!

Regular water testing and monitoring

As a responsible aquarium owner, it is crucial to regularly test and monitor the water in your cold-water fish tank. This helps ensure that the water quality remains optimal for your aquatic pets' health and well-being.

Regular water testing allows you to keep track of important parameters such as pH levels, ammonia levels, nitrate levels, and temperature. By conducting these tests on a consistent basis, you can identify any potential issues early on and take appropriate measures to address them promptly.

Maintaining good water quality is vital for the overall health and longevity of your cold-water fish, so make it a habit to incorporate regular water testing into your aquarium care routine.

Feeding appropriate diet and quantities

Feeding your cold-water fish the right diet in appropriate quantities is essential for their health and wellbeing. Coldwater fish typically have slower metabolisms compared to tropical fish, so they don't require as much food.

It's important to provide them with a balanced diet that includes high-quality flakes or pellets specifically formulated for coldwater species. Additionally, supplement their diet with frozen or live food like bloodworms or brine shrimp to add variety and ensure they receive all the necessary nutrients.

Remember not to overfeed your fish, as uneaten food can quickly pollute the water and lead to health issues. By carefully monitoring their feeding habits and providing them with a nutritionally complete diet, you can help keep your cold-water fish happy and thriving in your aquarium without a heater.

Performing regular tank maintenance

Regular tank maintenance is essential for keeping your cold-water fish healthy and thriving in your aquarium. It involves tasks such as performing water changescleaning the tank, and monitoring water parameters.

By regularly maintaining your tank, you can ensure optimal water quality and minimize the risk of common issues like ammonia spikes or algae blooms. Regular water testing will help you keep track of ammonia, nitrite, nitrate levels, pH, and temperature to ensure they are within the appropriate range for your fish species.

Cleaning the tank includes removing any uneaten food or debris from the substrate and decorations. This prevents the buildup of waste that can negatively impact water quality. Remember to avoid using harsh chemicals when cleaning; instead, opt for aquarium-safe cleaners or simply rinse with warm water if needed.

Additionally, regular equipment checks are important to make sure all filters and heaters are functioning correctly to provide a clean and stable environment for your cold-water fish.


In conclusion, there are several cold-water fish species that can thrive in your aquarium without a heater. These include the White Cloud Mountain Minnow, Celestial Pearl Danio, Hillstream Loach, Endler's Livebearer, and Cherry Shrimp.

When choosing cold-water fish for an unheated tank, make sure to consider their temperature tolerance and compatibility with other fish. With proper care and attention to water quality, you can create a beautiful and successful cold-water aquarium without the need for a heater.

So go ahead and explore the world of non-tropical fish species - they may just be the perfect addition to your home aquarium!


1. What cold-water fish can live in an aquarium without a heater?

Some common cold-water fish that can thrive in an aquarium without a heater include goldfish, koi, white cloud mountain minnows, and hillstream loaches.

2. How do I maintain the right temperature for cold-water fish without a heater?

To maintain the right temperature for your cold-water fish without a heater, you can place your aquarium in a cool room away from direct sunlight or use fans to create air circulation and lower the water temperature. Regular monitoring of water temperature is crucial to ensure it stays within the acceptable range for your specific species of fish.

3. Are there any special considerations when keeping cold-water fish without a heater?

Yes, there are some important considerations when keeping cold-water fish without a heater. These include ensuring proper filtration and oxygenation of the water as colder temperatures decrease oxygen levels; feeding them appropriate food for their specific dietary needs; and providing shelter and hiding places in the tank to mimic their natural environment.

4. Can I mix different types of cold-water fish in an aquarium without a heater?

In general, it is possible to mix different types of compatible cold-water fish in an aquarium without a heater. However, it's important to research each species' requirements regarding water parameters, compatibility with other species, and overall size compatibility before introducing them into the same tank. Consulting with knowledgeable pet store staff or aquatic experts can help you select suitable combinations that will coexist harmoniously.