Coldwater Aquarium Fish

If you're interested in starting up an aquarium of coldwater fish, it's probably good to know which fish those are. You want to make sure that they can be placed in that kind of environment and survive. As with most blogs I write about, be sure to check and make sure that the fish you put together in a tank can co-habit well before throwing them in together.

The most common coldwater fish is the goldfish, followed closely behind by the koi. There are many other fish that do not require a heated tank. Many are even large enough that they are only suitable for ponds, but the following list of fish are specifically coldwater fish that can actually be set up in an aquarium because they are small to medium sized.

1. Barbs. There are a number of different species of barbs available, and all are easy to care for and suitable for a community aquarium.
2. Bloodfin Tetra. Both the standard and false bloodfin can tolerate temperature as low as the mid sixties. They are offered in many pet shops, are easy to care for, and pretty hardy. They are usually top dwellers and are best kept in schools.
3. Buenos Aires Tetra. They can also tolerate temperatures into the mid sixties. They are undemanding and easy to care for, as well. Very suitable for a community tank, but will eat live plants.
4. Croaking Tetra. These are harder to find on sale, but they are an attractive fish that is worth shopping around for. They are easy to care for and suitable for community tanks.
5. Guppy. There are many attractive variations of this popular fish and usually available at most pet shops.
6. Hillstream Loaches. They're not often found in pet stores, but can be found for sale occasionally. They don't all prefer cool temperatures, but most can tolerate temperatures that fall into the mid to upper sixties.
7. Native Fish. This is a variety of North American native fish that are now being sold in the aquarium trade. Most can tolerate cool water and vary in size. 
8. Pearl Danio. This fish is hardy and easy to care for. Can tolerate temps in the mid 60s and is easy to find.
9. Weather Loach.This is one of the easiest fish to care for. It can even tolerate waters into the fifties.
10. Wimple (or batfish). This is not very commonly found and is an unusual fish, but worth tracking down if you want a unique fish.
11. White Cloud Mountain Minnow. One of the easiest to care for and do best in cooler temperatures, although very low temps will lessen their attractive coloration.
12. Zebra Danio. Most readily accessible fish, besides the goldfish and guppy. They tolerate temperatures into the mid sixties and are easy to care for. 

There are even more coldwater fish than that, but that list should give you enough options to at least start your aquarium. If you decide to venture out and put this tank together, have fun and good luck.