If you’re thinking of setting up a low-maintenance aquarium, or you live in a region with a cooler climate, you might want to consider keeping fish that don’t require a heater. Cold-water fish species are ideal for environments where you don’t want to rely on a heater to regulate the water temperature. These fish can comfortably thrive in water temperatures that range between 60°F and 75°F (15°C to 24°C), making them perfect for room-temperature aquariums. Find out now with Fish Lover Zone!
Here are some of the most popular and easy-to-care-for fish that don’t require a heater.
Top 8 Fish That Don’t Require a Heater
1. Goldfish (Carassius auratus)
Perhaps the most well-known cold-water fish, goldfish are beautiful, resilient, and come in a variety of colors and fin shapes. They can live for decades with proper care and don’t need heated water, as they thrive in temperatures around 65°F to 75°F (18°C to 24°C). However, goldfish grow large over time and produce significant waste, so it’s important to provide them with adequate space and a good filtration system.
- Ideal Tank Size: Minimum 20 gallons for a single fish
- Water Temperature: 65°F to 75°F (18°C to 24°C)
- Care Level: Moderate (due to tank size and water quality needs)
2. White Cloud Mountain Minnow (Tanichthys albonubes)
A smaller, hardy species, the White Cloud Mountain Minnow is perfect for beginner aquarists. These fish are peaceful and can be kept in small groups. With their shimmering colors and active behavior, they are visually appealing and thrive in cooler water. They can live comfortably at temperatures ranging from 60°F to 72°F (15°C to 22°C), making them ideal for unheated aquariums.
- Ideal Tank Size: Minimum 10 gallons
- Water Temperature: 60°F to 72°F (15°C to 22°C)
- Care Level: Easy
3. Zebra Danio (Danio rerio)
Another popular choice for unheated aquariums, Zebra Danios are active and social fish. Their striking stripes make them visually appealing, and they are incredibly hardy, making them perfect for beginners. They can tolerate a wide range of water temperatures, from 64°F to 74°F (18°C to 23°C). These fish are best kept in groups of five or more to encourage their natural schooling behavior.
- Ideal Tank Size: Minimum 10 gallons
- Water Temperature: 64°F to 74°F (18°C to 23°C)
- Care Level: Easy
4. Rosy Barb (Pethia conchonius)
Rosy Barbs are known for their vibrant colors and energetic nature. They are hardy and can adapt to a variety of water conditions, including cooler temperatures. These fish prefer temperatures between 64°F and 72°F (18°C to 22°C). They are best kept in groups and make a great addition to community tanks, as they are peaceful yet lively swimmers.
- Ideal Tank Size: Minimum 20 gallons
- Water Temperature: 64°F to 72°F (18°C to 22°C)
- Care Level: Moderate
5. Paradise Fish (Macropodus opercularis)
The Paradise Fish is a stunning species with its beautiful, flowing fins and vibrant colors. These fish are highly adaptable and can survive in cooler water temperatures, ranging from 60°F to 75°F (15°C to 24°C). However, they can be territorial, so it’s best to house them with compatible tankmates or keep them in species-only tanks.
- Ideal Tank Size: Minimum 20 gallons
- Water Temperature: 60°F to 75°F (15°C to 24°C)
- Care Level: Moderate
6. Dojo Loach (Misgurnus anguillicaudatus)
Often referred to as the Weather Loach, the Dojo Loach is an interesting, eel-like fish that is active and fun to watch. They are highly tolerant of cooler water and can thrive at temperatures as low as 50°F (10°C). Dojo Loaches are bottom-dwellers and like to burrow, so be sure to provide a soft substrate. They are also social fish, so it’s best to keep them in groups.
- Ideal Tank Size: Minimum 30 gallons
- Water Temperature: 50°F to 75°F (10°C to 24°C)
- Care Level: Moderate
7. Hillstream Loach (Sewellia lineolata)
Hillstream Loaches are fascinating, algae-eating fish that are perfectly suited for cooler water tanks. These fish have a unique appearance, resembling small stingrays, and are excellent for controlling algae in your aquarium. They prefer well-oxygenated water and temperatures between 60°F and 75°F (15°C to 24°C). They thrive in tanks with good water flow and lots of hiding spots.
- Ideal Tank Size: Minimum 20 gallons
- Water Temperature: 60°F to 75°F (15°C to 24°C)
- Care Level: Moderate
8. Pepper Corydoras (Corydoras paleatus)
Peppered Corydoras are small, peaceful bottom-dwellers that do well in groups. These fish are a great addition to community tanks and can tolerate cooler water temperatures ranging from 65°F to 75°F (18°C to 24°C). They help keep the tank clean by scavenging leftover food at the bottom.
- Ideal Tank Size: Minimum 20 gallons
- Water Temperature: 65°F to 75°F (18°C to 24°C)
- Care Level: Easy
Final Thoughts
Keeping fish that don’t require a heater is not only energy-efficient but can also be a simpler setup for those looking to maintain a low-maintenance aquarium. Whether you prefer the graceful goldfish, the lively Zebra Danio, or the unique Paradise Fish, these cold-water species offer a variety of beautiful and easy-to-care-for options.
Make sure to provide adequate filtration and water quality to keep your fish healthy and thriving. Cold-water aquariums can be just as exciting and diverse as their tropical counterparts!
