Get ready we have something coming that is going to blow you away.
We are about to release a real life simulation game called "Darwin's Aquarium". This is the place to start training and breeding your first artificial intelligence to control the fish in your aquarium. Make sure to set up the aquarium correctly and let the evolution start! Be watchful of the water quality and light setup. Ensure the environment contains right amount of nutrition, oxygen and salt. Place some algae, anemones and, of course, some fish! Let them hunt, cooperate or evade each other. They'll mutate and being selected, either by nature or by you.
And remember: The survival of the fittest does not mean the strongest or the best. It means that the most adaptive species will survive.