yes of course.... substrate will effect your fish, he will feel safe and comfortable, you may choose a light or dark color of substrate according to the type of your fish
yes i deffintly does but in the case of the fish u have you should deffintly go wit a natural color gravel. i tend to like usiung a mixture of natural, brown, and black gravel the black is there just to break up the light colors dont use to much blk, and crushed coral