Splash! Real-Life Mermaids Seek Beauty of Deep

Fraser is also in the front lines of ocean activism, where danger is just as real above sea level. She was attacked by fishermen while peacefully protesting the annual slaughter of dolphins in Taiji, Japan. The chilling moment was captured in the Academy Award-winning film "The Cove."

"[The fishermen] were extremely angry," she said. "They didn't want to be filmed. And they started backing up their boat propellers right up to our legs. We were that close to spinning boat propellers. And as soon as this guy started pulling out this huge long stick I was like, that's when the fear set in."

The battling forces of culture and conservation continue today. But Fraser's work to defend the earth's oceans as her mermaid alter ego is not solitary. Believe it or not, Fraser is not the only mermaid out there.

Fraser has an underwater colleague in mermaid Linden Wolbert.

"The first time I went underwater and I was out with the fish, looking at the light shining through the kelp, I started to cry," said Wolbert. "It was real. And I dreamed of it my whole life. It was amazing. It was life-changing."

Wolbert's tears of joy at discovering the water led to a new calling.

Like the fictional Aqua Man, Wolbert seems to draw oxygen from the sea. Remarkably, she can hold her breath for nearly five minutes.

David Warth

Hannah Fraser as a mermaid.

"When you do a long breath hold, your diaphragm begins to contract and that's telling you, 'Hey, you're supposed to be breathing,' and you have to learn to tolerate the discomfort of that feeling," said Wolbert. "And once you can achieve that, you can go for quite awhile."

As Wolbert was building her stamina and physical discipline for a life underwater, heartbreak changed her destiny.

"My grandmother ended up becoming sick with cancer," she said. "And the last time I saw her she said, 'Whatever you do, take your gifts and follow your dreams into the ocean.' And I said OK, and she had left me an inheritance. And with that I created my mermaid tail."

Wolbert's dream began to take shape when a remarkable collaborator agreed to build her a one-of-a-kind mermaid tail.

Allan Holt is a special effects artist whose creations have been seen in numerous Hollywood blockbusters.

"When we started this project, my days were [spent] on movies like 'Terminator Salvation' and 'G.I. Joe,' and then I would go and work on the mermaid tail at night," said Holt. "During the days, it's things like carnage and blood. And then at night, it's water-colored paintings of mermaids, and should I have a harp? And should there be gold? What if there's a harp and gold and there's seashell bras? And then the next day it's: How do shotgun shells go through flesh and hit metal underneath and what does that look like? The balance was fun."

Mermaids: 'Immense' Propulsion

After seven months and countless re-workings of the tail, Wolbert and Holt's unique partnership yielded a functional work of art. Wolbert showed it to "20/20" at the Sea Life Aquarium in Carlsbad, Calif.

"It's roughly 35 pounds of silicone. The propulsion I get from this tail is immense. Everything is coming from my core, just like a dolphin," Wolbert said. "So, I am able to really feel the wind through my hair, so to speak, in the water. People can't keep up with me. I can keep up with fish in marine life very easily. I can keep up with the best of them. Being able to swim as fast as a dolphin or close to it is a pretty amazing thing."