If you want to sell fish, I think that whoever mentioned "supply hard to find fish" had it right.
Somebody selling feed-trained SMB and LMB, tilapia, feed-trained YP, and such would probably have a good, regular market for himself. Every fish hatchery out there seems to sell LMB, BG, CC, GSH, and FHM. You want to sell fish that people can't get elsewhere and have to get every year or few years.
