Is there any acrylic paint that is clear and I can use in an aquarium? My fish keeps trying to attack his reflection.?

You could try re-positioning the tank in different lighting that doesn't show his reflection as well. The only thing that's really safe for tanks would be potable epoxy like marineland's sillicone. I don't know how it would make the tank look though. It would probably look pretty ugly if you covered the whole tank in that. You could try adding some more plants in his tank so that he doesn't see the glass as often. Flaring isn't really bad for him unless his fins start ripping from doing it too much.

The same thing happened to my fish too sugar, and one thing that helped me was to paint the outside of his take a light blue, another thing I also tried was I printed out colorful sheets of coral reefs and taped them to the outside of his tank , it worked at first. Unfortunately, the tape I had wasn't strong enough so I just ended up painting the outside of his tank and believe it or not it worked!! I hope this advice helps with your fish ;)