Krylon Fusion can be used on the inside as well as the outside. I've painted loads of PVC pipe for the fish to hide in/play in and it can be used in the tank when it drys.
I know it comes in a spray can....not sure if it comes in a can which can be painted on with a paintbrush.
I've never done it on the inside to tell you the truth. Something to consider though. It would hide your trim problem if you painted the inside background black or blue.