Georgia Aquarium officials say a beluga whale has died unexpectedly while on a temporary stay at Sea World in San Antonio.
Greg Bossart with the aquarium said Monday that Nico, a 25-year-old beluga, died Saturday morning.
He was scheduled to return to Atlanta in mid-December after renovations on the beluga habitat at the Georgia Aquarium are complete.
Bossart said an initial necropsy was inconclusive on what caused the death.
He said veterinarians are running more tests to determine why Nico died.
The whale came to Atlanta in 2005 from a Mexico City facility.
Bossart said the whale had intestinal and other medical problems dating back to his time in Mexico but seemed in good health recently.
The aquarium has two other belugas staying at Sea World until work is complete on their home in Atlanta.