You are a fish locked in the desperate game of survival in a small coral reef. As you struggle to live you'll learn about prey and predators in a reef.
Controls are simple, you move your pointer to guide your fish and click on fish to try and eat them. You can also move your fish behind coral and into caves to avoid predators.
There are several modes which mostly involve you gaining points by eating fish then exchanging those points to become a larger fish or one with other abilities. You can also use your points to make your own fish, the more points you have the more useful bits you can buy to add to your fish.