ive seen blind bichirs on here and they are really dark almost black,someone had said its because they cant see they think they are in a cave so they try to match their enviroment ....made sense to me sept for my bichirs when i have the lights off for any long period of time because i work a swing shift at a lumber mill i get home around 4 oclock in the morning i'll come home and turn the light on my tank on and after being in the dark for 12 hours + my bichirs are all washed out pale ,but after the lights are on for awhile they darken right up ....i have black substrate which im told gets them dark.....ive left the lights on when im gone and they dont loose there color....its just that cuz a bichir cant see he turns dark ,doesnt add up when they turn light when the lights are out and they cant see..................anybody got a thought.