The general rule with raising fish for sale is If you're doing it to make a profit, don't bother. The most successful fish breeders/sellers I know still don't make enough money to do anything with it. Plus, the people who do manage to make a living at this usually have to devote acres of space to their business. If you're just trying to make a little money back to take the edge of your expenses, then I wish you the best of luck, but if you're trying to make a profit, odds are you won't be able to without devoting an entire garage to it. I would also recommend that you start small. Guppies are easy to breed, easy to find, and always have a demand. Start with that, and then work your way up to the rarer stuff.