Less than two years after its lavish opening, Long Beach’s Aquarium of the Pacific is in the midst of a sophomore slump.

Attendance is down, which has caused a re-examination of budget projections and for a time threatened to hinder a $5.5 million bond payment due in June.

Aquarium and city officials say that payment will be met. But they concede there has been a drastic re-figuring of the aquarium’s formula for success. Some staff positions have gone unfilled, and the operating budget was cut from around $25 million to $24 million.

A chief financial officer is being brought on board within a month and the aquarium has hired accounting firm Ernst & Young to take a look at financial priorities.

“Of course we’re concerned, but it’s not a high degree of concern,” said Long Beach City Manager Henry Taboada. “I’d rather it wasn’t in this situation, believe me, but it’s not critical.”

In some ways, the facility was a victim of its own initial success. The combination of media interest and pent-up demand meant it had to spend very little on marketing during its first year. Now that it’s established, the aquarium must compete with the rest of L.A.’s attractions.

“We’d always anticipated that attendance would fall off in the second year,” said Warren Iliff, the aquarium’s president and CEO.

When the aquarium opened, officials believed it needed to reach annual attendance of 1.6 million. Iliff now says that figure might not have to be so high, and Taboada puts the figure at no more than 1.3 million.

Aquarium officials now expect attendance for the fiscal year ending Sept. 30 to hit about 1.2 million. They declined to disclose projected revenue.

That attendance would still make the Long Beach facility the third largest aquarium in the country, behind attractions in Chicago and Monterey, according to the American Association of Zoos and Aquariums.

But Taboada suggests the staff may know more about sea life than financial management. Cash flow has been quite good, he said, but when accountants were sent to check the books, they found much of the money had been put in a discretionary account that the aquarium thought it couldn’t immediately access.

“They were forecasting a shortfall, and my staff immediately showed them they had $1 million available,” Taboada said. “Anytime you have millions in the bank, and you can’t pay the light bill, something is wrong.”

The aquarium also has suffered because it was scheduled to open in concert with the Queensway Bay project, but construction on that large retail center is only now getting underway.