Genetic Engineering

I have decided to become a genetic engineer today.

I am going to breed guppies I figure I can have a new batch of guppies every 3 months. They are like little rabbits that live underwater.

I will start from just regular guppies at the pet store. Yah it will take longer, but what is the fun of getting a pure-bred to start off with? I want my guppies to be hardy, I will make the fish tanks come to the edge of dangerous levels of ph, nitrate, nitrite etc... The weaker fish will die off and I will have a strong breed and they will be cockroach of the freshwater fish tank, a nuclear bomb could go off and they will still live. I also think a lot of the pure bred guppies out there are inbred, so they might be purebred, but what good is a pure-bred slack-jawed yokel?

What will I do with all the extra guppies that I decide not to keep? I have some friends with oscars that will gladly eat them.