Think you are a little fish in a pond with bigger and smaller fishes around you. You need to eat smaller fishes to get bigger. Eat smaller fishes as much possible avoiding bigger fishes which will also try to eat you. Be careful about eel fishes to avoid electric shock. Mermaid will pause you for few moments with no control and risk to be eaten by others. Angler fishes are ferocious and will eat you in a moment no matter how bigger you are.
Tilt your device to move your fish. Grow bigger eating small fishes and increase your level to eat bigger fishes. Take pearls to get bonus life. Easy to play but addictive game for you and your kids.