I help advise what fish and colors my lfs sells because they almost turned to stocking dyed fish. When it comes down to it there are alot of very colorful fish out there that are naturally colorful that people can stock instead of dyed fish, mainly livebearers. People are always breeding brighter new colors in fish; you can get guppys in pink, blue, white, orange, yellow, red, purple, green, blach, grey, white, brown etc for example and they come in a variety of metallic sheens in them and patterns.
People buy dyed fish because of their color and rarely for what the fish actually is. I think to combat the dyed fish situation you need to educate people of all the wonderful colors already naturally available in fish and that dyed fish rarely ever have their colors last, let alone live.
When you combat people who only care about the money and image aspect of fish you need to persuade them that they can get better value for money with natural fish instead of trying to educate them about the moral aspect of it because they don't care about that. You can't change everything, and you can't give people morals either but i think this situation is more about finding a way to banning dyed fish than spending your time teaching people the morality of the situation...How you go about it is everything.