WATER is not his Kryptonite.

A 10-year-old swimmer named Clark Kent Apuada broke a swimming record that Olympic legend Michael Phelps set 23 years ago.

Apuada, who also goes by "Superman," finished the 100m butterfly at the Far Western Long Course Championships in California with a time of 1:09.38, over a second faster than Phelps' 1:10.48.

He ended up winning gold medals in every event he competed in at the meet, much like Phelps did at the 2008 Beijing Olympics.

The rising fifth grader has been swimming competitively for four years and targeted the event because of the chance to break Phelps' record, his mother Cynthia told the Huffington Post.

Clark already has his eyes on the not-too-far-off Summer Olympics. After all, Phelps was just 15-years-old during his first Olympics in 2000.

"Paris 2024 or Los Angeles 2028," he told the Huffington Post. "This record has motivated me to keep swimming, to keep striving and do everything I can to get to that elite level."

His name came about, his mother told Huffington Post, because she liked the name Clark and Superman was his father's favourite superhero.

"We're always just telling people his name is Clark," she said. "But when they realise his full name, people just call him Superman.

It fits, she said, since her son "is regarded as a superman in the water."