Keeping coldwater fish

You've probably seen goldfish and rosy red minnows at pet stores. They only cost a few cents, so why not buy some? Fish keeping can be expensive, but cold-water fish are relatively cheap pets. You don't need to buy a heater. 

You need the following equipment to keep cold-water fish:
Tank: At least five gallons for anything other than a Betta.

Filter: My five gallon tank has this filter http://www.petsmart.com/product/index.jsp?productId=2753028&lmdn=Fish+Filtration+%26amp%3B+Circulation

Gravel: I use some stones and gravel I found. Anything you put in your tank must be very clean!

That's pretty much it, but you can also add decorations and toys.

My goldfish and minnows play with small toys in their tank!

What kind of fish can live in cold water?

Goldfish: Comet or Common goldfish are very cheap. Goldfish are one of the more long lived fish. They have a reputation for being very messy!

A Common Goldfish and a Bubble-Eye Goldfish

Minnows: You can keep the cheap Rosy Red minnows, White Clouds (they look like neon tetras), or minnows that you catch your self.
Bettas: Beautiful fish! They are short lived unless you buy them as fry or breed them your self. Males must be kept separately! They can live in a fish bowl. Bettas can also live in heated water.

A male Betta

Danios: The Zebra Danio is very popular and cheap. Many other species are available as well. Glo fish glow under certain lights.
Guppies: Cheap and beautiful! They are also short lived. They breed very easily. They can also be kept in a heated tank.
Rosy Barb: Not all species of Barbs can be kept in cold-water, but the Rosy Barb can. They may be aggressive. They can also live in heated water.
Minnows and other small fish that you catch in creaks, ponds, or lakes can also be kept in your tank. Koi can be kept in aquariums when they are young and small, but they will soon need to live in a pond.