The wild Carnival Cruise all-out brawl -- supposedly over chicken tenders -- had a happy ending of sorts ... TMZ has learned that *nobody involved was arrested!

Law enforcement sources tell TMZ ... Miami-Dade Sheriff’s deputies were called to the crazy scene Monday after the ship pulled into port on the cruise’s final day.

The deputies conducted an investigation, interviewing Carnival staff ... but, in the end, they determined arrests were not warranted because no one filed a complaint.

In addition, the investigation revealed the ship's security stepped in, broke up the fight and made sure things didn’t get any crazier.

So yeah ... no one ended up in handcuffs, even though the brawl looked cluckin' insane -- and the guy who caught it all on camera joked it was over chicken tenders.

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