I've had what I would consider success through breeding guppies with having successfully raised several generations, I am doing this partly for fun but mainly for some extra cash. Today I started look on the internet for tips and I found that apparently you should buy "breeding stock"? I simply bought colourful fish from the shop and the babies have also been just as colourful, if not more. I don't really understand what breeding stock is, or where you buy said stock. Do you really need to because I don't understand why. Thanks for any help.