Reply #15: The easiest way to go would be goldfish.

[surrealAmerican]

They're hearty, grow fairly large, come in many colors and shapes, and are reasonably priced. They also don't need a heater in the tank (unless it's unusually cold in your house). You'll want at least a ten gallon tank. I've had good results with a "sponge" filter in this kind of setup, which is usually the least expensive option. If you have a cat you absolutely MUST have a full tank cover. As others here have mentioned, set up the tank with water and filter running a few weeks before you get any fish.