Best Fish for a Cold-Water Aquarium

If you want a small or low-maintenance aquarium, you may be considering forgoing the heater and operating your aquarium at room temperature. Unless you select new aquarium fish with cool temperatures in mind, you can expect tropical fish to meet an untimely death from living in an inapporpriate environment.

The following common, readily available fish species can surprisingly low water temperatures without it comprimising their long-term health. Although the choices for stocking a cold-water aquarium are limited, many beautiful and active species of fish are available to choose from.

Rosy Barbs

A member of the minnow family, Cyprinidae, the rosy barb is one of the most cold-tolerant of tropical fish, and has been selectively bred to accentuate this feature. They are fun, beautiful, and very suitable to community aquariums, so long as no long-finned or slow-moving tankmates are present. Rosy barbs can live at temperatures as low as sixty degrees before it begins to weaken them.

Guppies

While the guppy is a tropical fish that requires warm water to thrive, some well-domesticated strains of guppy will do quite well at lower temperatures, sometimes as low as seventy degrees. They are quite hardy and forgiving, making them especially ideal for first-time aquarists. Their small size makes them especially suitable to miniature cold-water fish tanks.

White Cloud Mountain Minnows

Another popular, hardy addition to a small home aquarium, the petite and gem-like White Cloud is a pleasant and easy-to-keep fish for cold-water aquariums. They are native to extremely wintry environments and some aquarists claim that they can even survive freezing (but please don't test this!). The White Cloud Mountain minnow's coloration grows duller at temperatures below the seventies, but it remains hardy even in the fifties.

Zebra Danios

Zebra danios, like guppies, are tropical fish that have been selectively bred for thousands of generations, resulting in dozens of distinct strains. Most of the domesticated strains of zebra danio are quite tolerant to cold waters, and can stay tough and active at temperatures in the mid-sixties. They are very easy to care for, petite, and suitable for a small tank.

Bloodfin Tetras

An active, feisty top-feeding fish, the bloodfin tetra is very hardy and lives well in cold-water tanks, including community aquaria. It is readily available in most pet stores and can tolerate temperatures as low as sixty degrees, and it remains beautiful and strong even in unideal circumstances and do best when kept in groups of five or more.