Fish and Plants That Don't Need a Heater for a Freshwater Aquarium

You can have a successful freshwater aquarium that doesn’t need a heater. A cool water aquarium, as it’s known, can work well, although it needs to be kept away from the windows which can bring natural heat. After setting up the freshwater aquarium, leave it empty for three days before introducing any fish. You will still need to use a filter in the freshwater aquarium.

Comet Goldish

The Comet Goldfish is an ideal fish for a cool water aquarium. Also known as the Comet-Tailed Goldfish, it’s not the same as the common goldfish but is a type of fancy goldfish.

The tail is heavily forked and much longer than that of the common goldfish. They come in different colors ranging from yellow to red and white. They’re extremely active and can reach up to 12 inches in length, with a lifespan that can last up to 14 years; expect a Comet Goldfish to live at least 7 years, so it will be around for some time. When starting a cool water freshwater aquarium, begin with just 3 of these fish in the tank and no others. It will also work well in cold water, even in outdoor ponds.

White Cloud

The White Cloud is a Mountain Minnow. It’s much smaller than the goldfish, just around 1 1/2 inches long. They like to be in schools of at least 5 fish, so you’ll need a tank that can accommodate that. Although classed as good starter fish, establish the freshwater aquarium before introducing them. The most common variants of white cloud are golden cloud and meteor minnow.

Dragon Fish

In spite of the name, the Dragon Fish is very peaceful. Around 15 inches long, it sticks to the bottom of the tank and eats Ghost Shrimp and black worms. It doesn’t see as well as most other fish and so can miss out on food in the freshwater aquarium, so the owner has to ensure it’s properly fed.


Anubias are good plants for a cool water freshwater aquarium. It’s very hard and adaptable, the roots attaching to a piece of driftwood; it doesn’t need a substrate in order to grow. It grows slowly and can be almost impossible to kill, making it ideal for a beginner. The plant will also live for a long time.

Java Fern

The Java fern shares most of the qualities of Anubias. It should be pointed out that the rhizome should not be planted in the substrate or it will rot. The Java fern is the most popular of the ferns and certainly the easiest to grow in a freshwater aquarium.


There are many types of cryptocorenes that will work well in cool water. If using small plants keep them close together. Larger plants should be more widely spaced. Use clean substrate and try to avoid uprooting them or they might die. If left they will prove to be very long-lasting and hardy and show themselves to be a beautiful addition to the freshwater aquarium.