Which fishes can be kept in cold water (without heater)?

Unlike other pets, keeping fishes in our house requires us to do a lot of maintenance work – frequent change of aquarium water, checking water pH and temperature, maintaining the heater, etc. For some of us lazy souls all this may become pretty overwhelming pretty soon.

So, if you still want to have fishes at your home or office, but do not want to constantly worry about a plethora of aquarium maintenance issues, you should opt for cold water fishes. Unlike warm water fishes, you need not install a heater for these fishes. This rules out at least one thing off the regular maintenance list.

Note

Aquarium heater is needed in cold countries. In warm countries, you probably won’t even need one. Well, maybe in winter season.

So, do some research on the annual and diurnal temperature variation in the place you are staying, and the temperature variation that your fish may comfortably be exposed to.

Table of Contents

• What are cold water fishes?
• List of Cold-Water fishes for aquarium

What are cold water fishes?

Cold water fishes are those fishes that can live in relatively cold or non-warm water or fresh water. So, they do not need us to artificially warm the water for them using a heater.

Though the ideal temperature for them may vary a lot. Some of them will be more comfortable at room temperature (say around 65°F or 18°C), while others may even survive in icy ponds. So, do a little bit of research on the species you want to buy.

And kindly do not start pouring ice cubes in your fish tank just because you think that a cold-water-fish needs freezing cold water!

As you may have guessed, things are not as simple even with cold water fishes. There are still some minute points that you will need to keep in mind. Let’s have a look at some of these cold-water fishes and dive a bit deeper.

List of Cold-Water fishes for aquarium

• Gold fish – It’s probably the most famous aquarium fish, and guess what – it doesn’t need a heater! That’s why many kids even place it in a bowl; About 12 inches (30 cm); pH 7 to 7.6; Can bear a temperature upto 30°C.
• White Cloud Mountain Minnow - About 2 inches (5 cm) in size; Can bear a temperature range of 4°C to 24°C; pH between 6.5 and 8
• Rosy barb and Gold barb – About 3 inches; Gold barb is a bit more aggressive than Rosy barb; pH 6.6 to 8.4 (all barbs are in general pretty adaptive); Can bear a temperature range of 12°C to 26°C.
• Dojo loach – About 1 foot; Can eat smaller fishes; pH 6.6 to 8; Can bear a temperature range of 20°C to 24°C.
• Golden Medaka – About 1 inch (3 cm) in size; Can bear a temperature range of 4°C to 26°C.
• Eastern Pygmy Perch – About 3 inches (8 cm) in size; A little high maintenance and need frozen and live food every month (so not for first-time fish enthusiasts); Can bear a temperature range of 4°C to 24°C.
• Murray River Rainbowfish - About 8 inches; Can bear a temperature range of 1°C to 22°C.
• Mosquito Fish - About 2-3 inches in size; Can bear a temperature upto 26°C; Eat mosquito larvae.
• Danios - About 2-3 inches; Can bear a temperature range of 18°C to 27°C; pH between 6 and 7.8.
• Gold Dojos - Belongs to Loach family; About 8 inches; Can bear a temperature range of 17°C to 24°C.
• Odessa Barbs - About 2 inches in size; Can bear a temperature range of 16°C to 25°C.
• Bloodfin Tetras - Can bear a temperature range of 18°C to 28°C.
• Bengal Danios - Can bear a temperature range of 18°C to 26°C.
• Texas Cichlids – About a foot in length; Can bear a temperature range of 20°C to 23°C.
• Paradise Fish - Can bear a temperature range of 10°C to 22°C.
• Buenos Aires Tetras - Can bear a temperature range of 16°C to 28°C; Need frozen and live food once in a while.
• Rainbow Shiner – About 3-3.5 inches; Can bear a temperature range of 15°C to 24°C; pH between 6.5 and 7.5.

Some other cold water fishes are:

• Sunset Variatus – About 2-3 inches; prefer water just above pH 7; can be placed in heated aquariums too.
• Celestial Pearl Danio – These are nano fishes and so can be kept even in small fish tanks; pH between 7 and 7.5.
• Endlers Livebearers – Standard Endlers livebearers are pretty hardy, but the new breed varieties need warm water; pH 6.6 to 8.4.
• Clown Killifish – Need to be kept in a closed aquarium (i.e. with a lid) as they can hop out of the aquarium; pH 6.6 to 7.6; Name is kind of a misnomer as they are pretty docile, not aggressive.
• Cherry Shrimp – A bottom crawler; Can survive even in frozen lakes that have ice on the top; Red in colour.
• Hillstream Loach – pH between 6.8 and 7.8
• Sumo Loach
• Rice Fish

Warning

For most of these cold-water fishes, or fishes in general, keeping them in the higher temperature ranges boosts their metabolism. This reduces their lifespan.