Fish Tycoon is a fish breeding sim game where you breed and care for exotic fish in a true real-time virtual aquarium. The object of this tycoon game is to discover the seven magic fish of Isola and solve the genetic puzzle.

You start with a small selection of fish, some money and a tank. You must breed your fish, care for them, help them grow, and cure them if they get sick. Along the way you can buy supplies, medicine and special chemicals; you can research technologies or invest in advertisement. All of this will be financed by selling exotic hybrids in your shop. The game runs in true real-time, so that if your computer is turned off or you exit the game, hours later small fish will have grown larger and new surprises await you.