A major Wall Street credit rating agency revised its outlook of the National Aquarium's finances to "stable" on Tuesday, after the nonprofit attraction at the Inner Harbor last year experienced a dip in its position because of the weak economy.

Last June, Moody's Investor Service cut the aquarium's bond rating from "A3" to "Baa1," which made it more expensive for the nonprofit to borrow money. The service this week affirmed the rating, which impacts $29.7 million in debt but changed its outlook from negative to stable.

Moody's said the change in outlook came after the aquarium experienced improved performance late last year and instituted better cost controls in the face of declining attendance this year.