You have a backyard pond and want to see if your koi would like the taste of some show guppies.
You have a community aquarium and wish to purchase my stock just to see if your fish carry any diseases
You have a major investment in one of the big pet store chains, enjoy visiting them to select your stock and enjoy visiting them often.
You live near a nuclear waste sight, your water is contaminated, and your purchasing my guppies just to see how plutonium makes all the pretty colors glow in the dark.
Stan Shubel is your neighbor and you have access to all his excess fish. (He's got alot of fish)