The fiancée of a billionaire banker’s son who died while trying to save her when she went overboard during a Florida fishing tournament doesn’t remember moments of the deadly accident, officials said.

Andrea Montero, 30, hit her head at some point when she went overboard as she and her fiancé, Juan Carlos Escotet Alviarez, 31, tried to snag a sailfish from a 60-foot boat — but she doesn’t recall if the injury occurred when she fell or when she was rescued by the crew, Florida Fish and Wildlife Conservation Commission officials told the Miami Herald.

“Rough as it was, she couldn’t say whether it was when she went over or coming back in,” FWC spokesman Jason Rafter told the newspaper. “She doesn’t remember when it happened.”

Montero and Escotet Alviarez — the youngest son of Banesco founder and president Juan Carlos Escotet Rodriguez — had been taking part in a fishing tournament organized in Key Largo when she fell from the vessel’s stern as it moved backward, FWC officials said.

Her fall roughly six miles off the coast of north Key Largo prompted Escotet Alviarez to leap into the water to save her, officials said.

He died when he was hit by the boat’s propeller, while Montero managed to avoid the large blades.

The banker’s family is now requesting privacy as they process his sudden death, according to a statement provided to The Post Tuesday by a Banesco USA spokeswoman.

“His family asks for privacy and respect from the press during this very difficult time as they grieve this tremendous loss,” the statement said.

Montero, who was reportedly set to marry Escotet Alviarez in November, could not be reached for comment, the Herald reported late Monday.

An investigation into the horrific incident is ongoing and additional details may take months before they’re released, according to the newspaper.

But authorities said the boat was moving backward when Montero fell overboard, indicating the anglers were likely fighting a fish at the time.

Professional anglers, meanwhile, said someone falling into waters as a boat moves backwards can spell disaster in an instant.

“If I’m backing down on a fish and someone falls in while the boat is going backwards, there is a real possibility that they are going to end up in the propeller,” said Larry Wren, captain of First Choice Charters.

Wren likened it to a car driving in reverse with someone atop its trunk.

“If you fall off, you’re under the vehicle,” Wren said, adding that anyone who comes in contact with large boat propellers isn’t likely to survive. “It’s a tragedy, but it can happen any day. It’s the same as a marlin jumping into the boat and spearing someone. It happens.”

Escotet Alviarez was a director at Banesco USA, a divison of Venezuela-based Banesco, the country’s largest private bank, according to its website.