Don't know what caused it but most of the owners don't keep water in the Vivs. It can breed Bacteria, they poo in it then drink.
I would remove the water bowl.
When my dog had pups she stopped birthing and rushed her to the Vet-they gave her a shot and she started again. Don't know how but one of the pups had fluid in his lungs. I watched the Vet guard the pups head and neck and spine between his hands. I then watched him put the pup outstretched even with his waist then swing the pup downward to a little past but between his knees legs were spread. He said gravity will do the trick just need to protect from anything being jarred in the swing.
Elliot my beardie in the tub stuck his head under don't know what he did for that split second but was opening his mouth really wide kind of bug eyed looking.
I did what the vet did to that pup and a itty bit of water came out his mouth. He was fine after.
I do not know if this is recommend, or I got very lucky. see what other people say on this before doing it