To make a mermaid appear, complete a level without dying once. She will drop starfish bubbles that can be quickly collected for extra points. The mermaid always appears from the last side where a fish was eaten.
After you gain enough levels you will be able to jump out of the water and eat flying bugs. To get extra points, eat an entire swarm. You can also earn style points by flipping in the air. You will get stunned if you land incorrectly and be vulnerable to predators.
There are bonus timed levels that start between levels that allow you to earn time bonuses. You will have one minute to eat 100 fish, bugs, or other targets. After all 100 are eaten you will earn the bonus. Note: Collect the clocks when they appear to add three seconds to the timer.
Bite his antenna to get his attention. Note: After you defeat him with Goliath he will gain the sucking ability. Lure him to a nearby sea mine. He will get dizzy and release some mushroom bubbles. Eat the bubbles to drain his health. Repeat this a few times, and he will shrink and your character will chase him.
Eat fish smaller than yourself and avoid the larger fish. A predator is larger than you and will eat you. You will lose a life when eaten. To get larger, eat smaller fish. Your fish will say "Yummy" when you have grown. To get more points, bite the tails off larger fish or eat an entire school of fish.
Eat a mushroom just as a pelican flies over it to shrink the bird. You can eat shrunken pelicans.
To eat the pelican that flies over the sea or the one that swoops down to eat fish, eat a mushroom bubble when it is flying over the sea. It will shrink everything that is bigger than you, including the pelican. Jump out from the water to catch and eat the pelican.
Eat fish quickly to fill your frenzy meter. When your frenzy meter is full, you will get double points for each fish eaten. If the frenzy meter is filled twice, you will earn a double frenzy bonus. When this happens, you will get triple points for each fish eaten. If you eat a 2x bonus bubble during a double frenzy, you will get six times the normal point value of the fish.