Titanic, coupons and a manta ray named Nandi are big hits at the Georgia Aquarium.

The downtown Atlanta attraction had its first year-over-year increase in attendance in the month of September, said Mike Leven, chief executive officer of the nation’s largest fish tank. Attendance was up 4 percent in September compared to the same period last year.

The news comes after Leven instituted changes at the attraction this summer, bringing in the traveling Titanic exhibit, promising to add more “wow” factor fish and creating “bounce-back” coupons that allow visitors to return at discount prices. He also made management changes, including accepting the resignations of two key officials that had opened the aquarium in 2005.

“Clearly, I think this proves our strategy,” Leven said.

The Titanic exhibit, he said, has been especially successful. A survey of 300 visitors found that about 80 percent said they came to the attraction for the exhibit first and the aquarium second.

“I don’t know how long it will remain at that level,” Leven said.

Attendance was up 12 percent over last September’s level until the gas crunch at the end of month, Leven said. The aquarium saw its visitation start to slow after motorists began having difficulty finding fuel.