I sell all of my fish online to people in my city and the surrounding area. I advertise them as what they are, high quality, healthy stock better than what is available at the lfs. At least around here, people seem to have an appreciation for quality stock as I am always still receiving e-mails for fish once I have sold all the ones for sale. I don't do anything rare, guppies, barbs, swords, endlers. I just take excellent care of my fish and it shows when people come to view the fish. All of the unfit fry are culled long before they attain any size, unlike fish stores which constantly have deformed or unhealthy stock. Granted, I sell a bit cheaper than the fish stores, but I don't have as much overhead.
At very best, I hope to recover what I've spent and what I continue to spend on electricity before the lease is up and I have to disassemble everything. If I end up back in my home town my mom is extatic about the idea of me raising discus in the basement, so I'd probably do something like that. I think Discus are probably one fish you could make a profit off of, if you are able to raise them efficiently. In my city, only one LFS ever has discus, and only 2 or 3 of size and they arent very nice ones.
Fortunately, even keeping discus is difficult for the average fish keeper and breeding them even more difficult so I can hope the market will remain open. In sum, I think it is possible, if you're good at it, to get it profitable. It just takes time, and a knowledge of your market. The initial poster's ambitions were... outrageous.