If you've ever set a goldfish free, who knows . . . maybe it THRIVED in the wild and became a GIANT, MONSTER GOLDFISH?  Because those are REAL.

Earlier this month, 25-year-old Mike Martin was ice fishing in Lake St. Clair in Michigan and caught a THREE-POUND, 15-INCH GOLDFISH.  The average goldfish is usually HALF that weight and that length.