Theres a few ways to make any fish have a glow to it here are some ways here.
1.On a dark color fish like a acie a bright light geting attracted to the dark color it will make your fish that bright.
But a downfall is that some fish don't like lights!If you have catfish they might die from stress or lack of searching for food from the light.
2.High Protien
Protien is great to feed your fish.It will help your fish enchance there colors.If you feed a red tail catfish shrimp the colors on its tail will darken up and be soild red.If you feed your oscars,catfish,gars, and other fish eaters there colors will enchance also.
Another downfall is if you feed your fish to much fish they will reject there regular feeding basis and wont eat anything but fish that will cause your fish to eat each other.This shouldn't happen if you feed your fish other fish more then once a week.
These are some solutions for colors.