ATLANTA - A prized whale shark at the world's largest aquarium died Thursday night, the second death of a popular animal at the center in 10 days.

Ralph, one of four whale sharks in the only such exhibit outside Asia, arrived at the Georgia Aquarium in June 2005 from Taiwan, where he had been destined to become seafood. The cause of death was not immediately determined.

"Recently, he has not been eating well and has had some unusual swimming patterns," aquarium spokeswoman Donna Fleishman said. He was moved to another part of the tank after he stopped swimming and died eight hours later, Aquarium executive director Jeff Swanagan said.

Ralph was considered a teenager.

Ralph and Norton, the aquarium's other male whale shark, arrived together and were joined a year later by two females, Alice and Trixie, in their 6 million gallon tank.

Whale sharks are the world's largest fish, growing up to 50 feet long.

Gasper, one of the aquarium's five beluga whales, was euthanized Jan. 2 after months of declining health.