From Towleroad:
"One of the largest tanks in the world, the aquarium features the world's largest viewing panel at 32.8 meters (107 ft 7 in) wide and 8.3 meters high. It was designed to hold more than 33,000 living animals, representing more than 85 species including over 400 sharks and rays combined, according to Dubai Mall's website. A Reuters witness said the mall, operated by Emaar Properties, had been partly evacuated and dozens of emergency vehicles were outside. Six divers entered the tank and appeared to be coordinating with workers outside the glass. Laborers mopped up water from the floor."
I just hope there were no Killer Whales up in there ...