But the aquarium, which houses more than 10,500 animals, is still standing, WBIR reported.
Ryan DeSear, Tennessee Ripley Attractions general manager told the television station that he wasn't sure if the flames reached the building, but said the webcams were still broadcasting overnight Monday and that the building itself was still there.
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"As long as we have fuel in our generators, that aquarium can run on its own," DeSear said.
The aquarium is built on a bunker and steps were taken to ensure the safety of the animals, WATE reported.
The fire was only 50 yards from the building when workers were forced to leave their stations.
Many vowed not to leave because they didn't want to leave the animals behind.
"They were (forced to evacuate). To them, every animal has a name. You don't give that up," DeSear said.
He was one of the last to leave the building Monday evening. He said he checked on the animals before he left and all were acting normally.