I raised guppies once and selectively bred to get a black body with a electric blue tail, they were beautiful! I ended up giving them to a pet store when I didn't have room for an aquarium where I moved. I think a lot of pet stores raise them and goldfish to use as 'feeders' for the meat eaters. It sounds cruel but like above I guess no worse then flushing them. I don't like to see ANYTHING die, I don't even like to think of where my hamburger comes from.