i used my camera phone so the quality isnt that good, but he did change alot. i also have a female fh on the other side could that be one of the reasons too? here is another pic of him when i 1st put him in and one of the next day.
your light is making your gravel glow and it is lighting up the whole tank. even your flowerhorn looks orange. fi sh do adapt to their suroundings though.
Yes gravel Does affect the color of your fish mainly its shade light colored substrate will lighten or wash out your fishes color and dark colored gravel will darken your fishes color
it seems with red devils and midas cichlids red gravel really makes them turn red while white or no gravel makes them pinkish to orange
Usually any change in color will happen over time like in a few weeks to a couple months not in a day or two but stress and other fish will also affect the color of your cichlid