Michelle
I am NOT artistic. This paint is very forgiving.
Smudges with earthy colors end up looking like wood. You could use a sponge.
You could practice on a spare pc of old picture frame glass.
If you were to decide to silicone it ( or something else) into place , he would have to be removed from his tank for days after the odor is gone.

Lija,
Thank You.
Hmmmm ? There is never a risk of the tape sticking to the frog? Does it stick in the humidity and/or to the styrofoam?

I like to keep my tree frog enclosures simple on the inside. I makes it much easier to keep things clean !!!

Lynn