In the world of Oceanar, your goal is simple: amass an army of loyal fish followers. The more food you eat, the more other fish seem to like you. It doesn't bother them that you are don't share the food ... they seem happy enough just to trail in your wake as you gobble down tiny crustaceans. You can even sic your fish army on jellyfish and rival schools. Just float your minions near them and a bloodbath will ensue. As you gobble plankton and grow your army, your rank increases. The sky (surface?) is the limit!
Use the mouse to guide your fish. Clicking the mouse makes your fish's light shine brighter, summoning your school. Eat food to increase the size of your school, making you a more potent attack force.
When you are just starting out, stay away from jellyfish and larger schools of fish. As you get bigger, send your minions to attack the jellyfish for a boost. Target smaller schools and take them out. Use your lantern to summon your army when you are ready to take out an opponent. If you find freefloating grey fish or crabs, you can add them to your team by swimming near them. When you start looking skeletal, focus on eating food to restore your health instead of attacking.