Mollies are far too large for an Edge, even if you didn't have the tetras.
If the tetras are Boehlkea fredcochui or Mimagoniates microlepis, which are the two species most commonly sold under the 'blue tetra' name, they also grow too big for an Edge. I'd return them if possible.
You want micro fish, like the smaller tetras (yours get to 6cms or so, adult size) or rasboras, or male Endler's or guppies.
Is the tank cycled at all? Are you testing the water every day?