You will see some fish surfacing, asking for food. They stay only for a while and then... Poof! Vanish. Your goal is to remember their locations and feed them some nuts. Select all the cells which had fishes and click- GO! Honey, you can't afford to make too many mistakes and you don't have forever!
I am Gundoo Paravai, the roundest penguin in Antarctica. I am starving here, and it's all your fault. Now go and make up for it. Feed my fish.