Fish Tycoon

Screenshots (click to enlarge)

In this fish-breeding simulation game, you're in charge of a real-time virtual fish store. Start with a small selection of fish, a little bit of cash and a tank. From there, it's up to you to breed, care for, and help your fish grow. Advertise to get a bigger customer base and finance purchases of food and medicine by selling your rare species. Take a break anytime you want. This real-time aquarium simulation will keep going when you're not around even if your PC is turned off!