I was just reminded... the story of Splatoon 3 starts with the Great Zapfish being kindnapped. Again.
But then the story never touches on that again. Contrary to Splatoon 1 and 2, you never save the Great Zapfish in the campaign.
So... is there any clue what happened with the Great Zapfish in Splatoon 3?
You find the Great Zapfish near the end of the campaign. During the 4th section of the Rocket Battle, (The Spirit Lifter: Steerage), you find the Great Zapfish inside a large container below the rocket.
Agent 1: AAAH! The Great Zapfish is in that huge container!
Agent 2: So this is where it's been. We need to bring it back! But y'know...later, or something.
Image from BeardBear's Splatoon 3 walkthrough (5:53:09)
It's implied that Mr. Grizz kidnapped the Great Zapfish to power his rocket. After you defeat Mr. Grizz, the Great Zapfish is returned to Splatsville and can be seen on the Battle Lobby Tower.
In Splatoon 3, the Great Zapfish is stolen by
Mr. Grizz and used as a source of power for his rocket, which he planned to use with the intent of covering the planet in Fuzzy Ooze. It is located in the steerage section.
Following his defeat at the hands of Agent 3, the Great Zapfish returns to Splatsville, resting on the Unnamed Battle Lobby Tower.
According to Inkpedia.
