The game consists of a specialized deck of 52 cards which depict various sea creatures on a food chain--plankton, shrimp, little fish, big fish, seal, shark. The higher the creature is on the food chain, the more types of creatures it can chomp. Creatures cannot chomp their own kind, nor can they eat anything higher up on the food chain. Nobody can chomp an octopus or an electric eel, which are special action cards in the game. The game plays rather like the old card game War, with the superior creature "chomping" the others and taking the trick. The first player to collect all the cards wins the game.
The rulebook includes several variations.