We recently bought a 5 year old ficus and have had it for about 2 months. My husband has been primarily taking care of it. Today I noticed that there was a white film on some of the leaves. We are brand new at keeping bonsais and still learning. Is this mold? What is the best treatment for this and how should I proceed? Thank you

Hello, thanks for posting.
Your Ficus in fact is an Elm.
The whitish film on the leaves could be from your tap water, if you manage to use rain water is better.
Otherwise please try to get a focused close up of the problem.

Agreed, probably from the water.
Just to be sure: Where in the world are you, and where are you keeping it?

Unless you get very deep winters, this plant does best when kept outside.