Silver Lyretail Molly With Issues

[Kayleen]

I got a lyretail molly yesterday and its mouth is kind of messed up, it looks as if it has teeth and it doesn't move its mouth and doesn't eat. I'm pretty sure it was not like this yesterday. Any thoughts?

 

[dkpate]

How long has the tank been running? Has it gone through the nitrogen cycle?
Is it white around the mouth?
What other fish are in the tank?
How big is the tank?

 

[Kayleen]

Died the day after...