There was nothing fishy about the motives of the Norwalk Aquarium Society. Proceeds from group's 35th annual Tropical Fish & Aquarium Equipment Benefit Auction on Sunday went directly to Earthplace -- The Nature Discovery Center, which hosts its monthly meetings.

For 35 years, in fact, the partnership between Earthplace and the society has gone swimmingly.

"We've had a long-standing, wonderful relationship," said Barry Lynch of Stamford, the society president.

"Earthplace hosts our meetings throughout the year," he said. "We have 10 monthly meetings, and in October we have a very big show and auction, and Earthplace is our host. In return, for the benefit of Earthplace, we host this auction."

"As a thank-you for being able to meet here, they put on this fundraiser for us every year," said Peter Fraboni, associate director of Earthplace. "Earthplace is very much involved in water quality ... so it's kind of a natural fit."

"Some of these guys do keep native species ... and also it fosters the care and husbandry of living thing," Fraboni said.

In fact, many society members raise fresh-water fish that are near extinction in the wild.

"We introduce endangered species back into the wild," said Sal Silvestri of Ridgefield, who's been with the society since 1975. "It's part of the whole environmental-ecology program we have."

For example, Lynch has been raising muzquiz platys, which are native to Mexico, but are practically extinct because of pollution.

"I brought in three bags, males and females, so that other people can breed and raise them," he said.

"A number of endangered species come from Mexico," he said. In some cases their original habitats remain polluted, so the fish bred in captivity can't be successfully reintroduced.

Along with ecological interests, however, for some club members the pleasures of maintaining an aquarium are simpler.

"Being in corporate, I found that if I sat in front of the tank and just watched them, it was very relaxing," said Silvestri, who calls the hobby "de-stressing."

"Fish make great pets," he said. "Some people think they just swim around, but a lot of fish have their own personalities. They'll recognize you when you walk in the room ... So instead of cats or dogs, fish."

The 60-year-old club draws about 65 members from throughout the region, mostly southern Connecticut. On the third Thursday of most months, these aquarium hobbyists meet and usually hear a presentation from a guest, conduct a mini auction of fish and supplies and share the company of fellow fish lovers.

"Earthplace is the perfect place for our meetings," Lynch said, who discovered the club as a great group to share his passion.