Originally Posted by Bulldog-fish
Might seem like a silly question but do fish prefer a certain light colour?
I have heard no, that they don't care but I swear I see a change in behavior based on my LED
color I choose. I have Electric Blue Acara and if I flip the deep purple or blue especially after a meal they show crazy pairing behavior. My theory is it makes them look more dark and blue to each other and triggers spawning (fish beer goggles). I observed similar changes with juvenile African cichlids although it was in aggression not spawning. All were male and each was dramatically different color. When I hit each color that enhanced each fish, the bright fish would take over the tank until I switched to the next color.
I would say if your talking about overall health then no, light color or on and off doesn't make a difference in their well being, but it makes sense to me that if it changes their appearance you most certainly can change behaviors between fish since color and appearance is such an important tool they use to communicate, choose mates, show dominance, etc within their own species and to other fish as well.
Good question though, I'm going to look it up and see if I can find a study that says for sure.