Hello fishguy,
Most killifish are best housed in a dedicated tank, although the more common ones will do fine in a community. Many of them are small enough that they can be kept in 5-gallon setups, but you must be well informed on tank husbandry. They are not generally recommended for the beginner aquarist, but they are not too difficult to keep, either. Again, the aquarists' skills plays an important part in all of this.
You can find some really interesting species on the internet. A lot of people sell the eggs, which eventually hatch when you submerge them in water. Some are annual and some live for two or three years. As compared to the more common fish we keep, they are really not long-lived fish. Specialized clubs and online auctions are the best places to find rare killies.
If you're new to the hobby, I would suggest giving it some time before you dive into them, so to speak. Learn as much as you can about them and when you honestly think you're ready, go for it!
David
