Within The body of every guppy there is a small group of cells placed in a protected position, for which all of the rest of the fish exists, called the germ plasm. In this respect also, the guppy is no different from other creatures, including ourselves. The germ plasm is not created by the fish; it creates the fish. He or she is only its custodian. Each generation springs from this most precious of all things in the world. Every feature about the natural guppy is but a trick of nature to see that the germ plasm goes on and on, always becoming better and better adapted to the environment. Improvement to us may mean greater beauty, longer fins and often features which make the fish actually more and more unadapted to its environment. But our fishes are our toys, our pastimes, and since we have created unnatural objects we have a duty to protect them, because they need greater care than the natural guppy