USA Olympic Swimmer Nic Fink Blown Away By Katie Ledecky's Consistency

It's not just swim fans that are in awe of Katie Ledecky's Olympic dominance ... 'cause USA gold medalist Nic Fink tells TMZ Sports he has no idea how she does it, either!!

Ledecky continued to make history during the 2024 Paris Games ... bringing home four medals over the course of the competition to become the most-decorated U.S. female Olympian.

We sat down with Fink while he was working an honorary shift at Raising Canes in Dallas, Texas on Monday ... and the 31-year-old swimmer -- who took home three medals in Paris himself -- gave his take on Ledecky's career thus far.

"The crazy thing is just the consistency," he said. "She's like, never been off. It's been on, on, on."

Fink explained it's hard enough for him to compete at his best ... but somehow, Ledecky always finds a way to take it to a whole 'nother level.

"I don't understand how she does it."

Fink goes way back with the women's swimming great ... as his wife -- Melanie Fink -- was a part of the gold-winning 4x200 relay team at the 2016 Olympic games alongside Ledecky.

Speaking of the Mrs. ... she could not attend the games in Paris as the couple is expecting to welcome a baby boy into the world. While he would have some impeccable swimming genes ... they don't plan on forcing the kid to live in the pool.

"He will hopefully be good at whatever he decides he wants to do," Fink said. "If swimming is the way, then that's his decision. But we're probably not going to push him towards that."

Looking back at his Olympic run, Fink was involved in one of the closet finishes at the games -- tying for the silver medal in the 100-meter breaststroke with Great Britain's Adam Peaty with a time of 59.05!!

Fink says the fact he was SO close to first place isn't the only thing on his mind ... saying, "Everyone says how close they are to gold, but I also think I was just as close to being off the podium entirely."