I tried it on a tank once (with green colored future board) -- looked quite nice, but I took it off after an hour -- with a very red Flowerhorn it just got too Christmassy lol.
With white, yellow, blue and green fish it will look OK. Orange maybe. But not for red, black, violet, purple, pink or such.
Consider your house décor, as the reflected light colors everything.
I have a bunch of different green colors for backgrounds on my tanks. For some reason, they look one or two shades lighter when water isin the tank. So go with the darker one.
If you can find a plastic table cloth that’s green you can give it a test drive before you commit to painting it. I had a black plastic trash bag as a background for 3 years and loved it.