No. Stonefish (Synanceia spp.) are native to the Indo-Pacific—Red Sea, Indian Ocean, western/central Pacific (Australia, Southeast Asia, Pacific Islands). They do not occur in the Atlantic Ocean, Caribbean, or Gulf of Mexico, where Miami Beach is located.
Miami Beach's coastal waters host different venomous marine life:
Stonefish antivenom is not stocked in Florida hospitals because the species is absent. If traveling to Indo-Pacific regions (Hawaii, Guam, Australia, Asia), learn stonefish avoidance: wear reef shoes, don't handle rocks/coral, shuffle in shallows.
Enjoy Miami's beaches—stonefish aren't on the guest list.