Hey, Allison!   I found a place that sells fish in smaller quantities, in case you were still looking, and it's in none other than Richmond, IL!     I believe they ship anywhere in the U.S., but shipping costs extra.    They sell in increments of 25 fish minimums for the smaller sizes (3-5 inch for the fish I'm looking at, which is yellow perch) and in increments of 10 fish minimum for the next size up (5-7 inches for the fish I want).   Let me know if you are interested, and I can send you a copy of the price lists.... they get the majority of their fish in the Spring... unfortunately, they don't have Tilapia though.... but mainly many of the game fish types that people stock in ponds, lakes, etc, including a decent variety of trout, which is one of the other fish I considered, because they can handle the cooler temps., and our basement tends to be cool in the summers, with a steady 62 degrees.   But I figured I might as well just get a heater, and then I can get whatever I feel like, at the time I buy a batch of fish... I'm thinking over time of changing fish varieties, and then I can process and freeze the extras as each batch gets to harvesting age. 

Anywhow, let me know if you're interested in info. from the place in Richmond.   I think it's called Keystone Hatcheries.