Gloop

Gloop is a friendly blue fish from Clanker's Cavern in Banjo-Kazooie. He supplies Banjo and Kazooie with much-needed air in the form of bubbles while the bear and bird try to raise Clanker by swimming through a key deep underwater. He blows sequences of bubbles every few seconds followed by a short rest.

Interestingly, Gloop cannot free Clanker despite being able to swim through the key needed to free him.

Trivia
Many players believe that the fish found in Hailfire Peaks that is later given to Boggy could in fact be Gloop because of its striking resemblance to the bubble-blowing fish.