Exploding Fish Tank Closes Casino

Fish tank deluge forces Gulfstream to close casino until repairs made

...Sfalanga was working in the casino the night the 13,000-gallon saltwater tank cracked.
She remembers around 100 people hanging out on the second floor, drinking or gambling near the 13-foot-high aquarium, the centerpiece of the room.

"All we heard was a big bang and all the water started shooting out the top of the tank," she said from her perch outside the casino. "It sounded like a cannon."

Within two minutes, all but two feet of water had streamed from the tank, Couch said.

The aquarium was home to more than 100 fish, including two small nurse sharks, angelfish, grouper and lionfish...

Breathtaking as it is, the aquarium may not be coming back, he said. "We're not sure of the outcome for the tank," he said. "We need to find out why it cracked open."

I've got a pretty good idea why, if not what triggered it.  A big round clear tank like that is almost certainly made of acrylic.  Acrylic absorbs water and swell, but only the side to the water swells.  This produces considerable strain.  Mostly, the tanks take the strain since the plastic is somewhat flexible, but once in a while the strain finds a flaw and shatters the tank.