Will Smith voices a fish who gets into trouble with the shark mafia

Shark Tale, starring the voices of Will Smith and Robert De Niro, took $49.1m (�27m) from Friday to Sunday.

If the estimated figures are confirmed, it will be ahead of Scary Movie 3's previous $48.1m record set last year.

"It's an incredible opening for any movie, not just for an animated movie," said Jeff Tharp of studio DreamWorks.

Mr Tharp, the studio's head of distribution, said Shark Tale gave DreamWorks its second best ever opening for a film, after Shrek 2.

US AND CANADA BOX OFFICE TOP FIVE 1. Shark Tale - $49.1m 2. Ladder 49 (above) - $22.8m 3. The Forgotten - $12m 4. Sky Captain and the World of Tomorrow - $3.4m 5. Mr 3000 - $2.6m Source: Exhibitor Relations

"We're particularly pleased with the urban market play as well as the suburban markets," he said.

"I think you attribute that to voice talent as well as the music in the movie."

Angelina Jolie and Renee Zellweger also lend their voices to characters, with Smith playing a funky young fish who gets into trouble with De Niro's shark mafia.

Ladder 49, a firefighting drama with John Travolta and Joaquin Phoenix, was another new entry at number two, taking $22.8m (�12.7m) over the weekend.

Paul Dergarabedian, president of box office tracker Exhibitor Relations, said the box office had been "flatlining" for the last month.

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"September was absolutely abysmal," he said. "So Shark Tale and, to a lesser extent, Ladder 49 really jump-started the marketplace."

Last week's number one, The Forgotten, starring Julianne Moore as a grieving mother, dropped into third.

Indie comedy I Heart Huckabees was another successful release, taking more than $300,000 from just four cinemas in three days.

Meanwhile, Tom Cruise's latest film Collateral was the most popular movie outside North America after strong showings in France, Belgium, Holland and South Africa, according to industry publication Variety.