Alright, well my $.02 is you should go totally exotic. Find fish that are typically sold as wild caught because they aren't mega-mart fish. I REALLY doubt you are ever going to make a penny trying to raise fish at home that are in direct competition with huge distributers. I would instantly rule out anything you can find any day at the petcosmarts of the world.
If you find things that people look for and can't find but can make a site that offers these exotic fish from UNUSUAL places then you are ready to ship some fish.
How about a rescue website for fish, and a retail outlet exclusively for breeding fish?
May sound silly but the best way to get rich quick is to write a get rich quick book. It may be a joke, but it's still true. Lots of people want exotic Asian and African mating pairs.. maybe you could be the matchmaker?