Lord Jabu-Jabu

Lord Jabu-Jabu is a large whale-like creature that serves as the guardian of the Zora in several games.

Ocarina of Time
Little is known about Lord Jabu-Jabu. In Ocarina of Time, he resides in Zora's Fountain, a sacred lake behind Zora's Domain, where he is worshiped by the Zoras and acts as a guardian deity similar to the Great Deku Tree. Jabu-Jabu is very fond of fish, and Young Link must feed him one in order to gain entrance to his belly to kill the parasite which ails him and save Princess Ruto.

Seven years in the future, Jabu-Jabu is mysteriously absent, leading some to believe he may have been killed by Ganondorf or fled into hiding.

Oracle of Ages
In Oracle of Ages, Jabu-Jabu once again lives among the Zoras in the Zora Village; only this time, they live under the sea. Link must go inside him to obtain Rolling Sea, an Essence of Time.

Other Appearances and Cameos
Jabu-Jabu has been compared to the Wind Fish from Link's Awakening, as both are god-like whales or whale-like creatures. He also shares strong similarities with Jabun in The Wind Waker; not only are they both large round fish, but Jabun's theme music is a remix of the dungeon theme for Inside Jabu-Jabu's Belly. Both of these deity-like fish also resemble the Ocean King from Phantom Hourglass on a lesser scale.

In the Lakebed Temple of Twilight Princess, sculptures that resemble Jabu-Jabu can be seen. Some of the Zora guards also wear masks that resemble Jabu-Jabu as he appeared in Ocarina of Time.

Trivia

 * 'Jabu Jabu' is a Japanese onomatopoeia for the sound of water splashing.