Six-year-old Yassin Eledkawi, a visitor from Vancouver, British Columbia, saw so many fish during a dive Tuesday on the Atlantis submarine that he wore out his camera battery taking pictures.

"I didn’t get to see a shark, but it was really cool," Yassin said.

The dive was a hit with his mother, Nayla Eltawil, and big sister 11-year-old Ayah Eledkawi, too.

"The kids liked it, and I got to see what’s under the ocean from the comfort of my chair," Nayla Eltawil said. "I wouldn’t go diving any other way."

Since Atlantis Submarines first dived into Hawaii waters Aug. 15, 1988, it’s provided a way for residents and tourists to stay dry while venturing just beyond the recommended diving limits that recreational scuba divers observe. After a quarter-century of underwater tours, the company has shared the mysteries of Hawaii’s undersea world with more than 7.8 million passengers on more than 225,497 dives.

Atlantis CEO Ron Williams, who was born and raised in Hilo, has spent his whole life on the water: surfing, paddling and enjoying the sights from a one-man canoe. However, even he still gets excited at the opportunity to see his company’s underwater operations.

"It’s awesome. I’ve been here 18 years, and every time I get in one of our submarines, I’m still like a little child," Williams said as he surveyed what he likes to call his "blue world" out of the peephole during a Tuesday dive. "You never know what Mother Nature will show you."

Along the route, Williams excitedly pointed out the natural and Atlantis-manufactured reefs that have created a home for honu (turtles) and slews of colorful fish ranging from the yellow, black and white pennant fish to the empress fish and a school of barracuda. As the submarine descends to around 130 feet, Williams said it reveals "a world seldom seen by anyone except scuba divers and fish."

Atlantis launched its first sub dive site off Kona in 1988 and followed that a year later with a dive site off Waikiki and one in Lahaina three years later. Today the company employs about 300 workers across all islands.

"We’re growing. Last year our revenues rose 13 percent, and we expect another single-digit rise on top of that for this year, which has had some weather-related challenges," Williams said.

Irrespective of Flossie, which closed down the company for two days, and the large south swells, which canceled dives for nearly five days, Williams said 2013 has been a costly year for Atlantis.

"This year we’re actually doing five refits, where we’ll strip the submarine down, change batteries and improve or replace our air-conditioning and soda (breathing) systems," he said. "We also are changing maintenance piers as part of the harbor masters plan. We’ll be making about a $2 million reinvestment. It’s a very expensive year for us."

Success for a water activity means looking for more exciting and efficient ways to do business safely and with showmanship, Williams said.

"We have to keep providing a reason for people to want to do us, and once they do we have to make sure that we give them a memory to take home. In the end that’s what will sell us," he said.

To that end, Williams has a bigger reinvestment in mind for Atlantis as it enters its next quarter-century in Hawaii, the most successful market for the company, which operates tourist submarines in the Caribbean, Mexico and Guam. He envisions buying a submarine that could take passengers about 600 to 1,000 feet below the surface. The company’s current subs are limited to 250-foot descents by design and 150-foot dives by regulation.

"We’re really talking about a deep-sea dive," Williams said. "You’d see less life than you do here because it’s really dark. But, we’d turn on lights on the way back up, and it would be really exciting. I’m sure there would be a market for it because people love adventure."

Delivery is still a ways out.

"If we said yes tomorrow, it would be about three years away," he said, adding that the expansion, which would add at least 12 full-time jobs, would have to be vetted by the Coast Guard and other regulatory agencies.

While the company got a rocky start when it revealed its initial plan to launch the business from Maui, over time it has proved to be a pioneer for the state’s burgeoning ecotourism business.

"When we tried to start in Maui, there were some concerns that it would be a Disneyland-style underwater amusement park. I don’t think we did a good enough job educating people about what we wanted to do. We went to Kona because the people were receptive, and that gave us time to prove that we are focused on being good environmental stewards," Williams said.

Each Atlantis submarine is battery-powered, emits no pollutants and moves quietly through the water to avoid disturbing fish and marine life.

Runoff made Waikiki largely devoid of activity, so Atlantis had to create a self-sustaining ecosystem for marine life to feed, repopulate and live. In 1989, at its Waikiki dive site, Atlantis, in conjunction with the University of Hawaii’s Sea Grant Program and state Department of Land and Natural Resources, introduced several artificial reefs to the area using sculpturelike concrete pyramid forms and ring structures, a decommissioned Navy ship, a Korean fishing vessel and two airplanes. Today the once desertlike 5.8-acre undersea tract is teeming with fish and marine life.

"I’m really proud of how the coral has grown," Williams said, "and become part of the circle of life."