Yes, colours in your tanksuch as substrate plus having lighting that's too bright can affect the colouration of your fish. Let's say you've got white sand, fish will often appear paler than if you were to have black sand. Having said this, not every fish well change colour. I've noticed a couple of my fish in the past change colour, especially when you put the lights on for the first time.
It's always best to try and give fish somewhere shady to hide, preferably underneath something if you can. Many Amazonian fish come from dimly lit areas of the river, like underneath mangroves and overhanging trees.
