Plecosterone: There's a black background, not so much visible in the detailed fish pic but in the others it's pretty easy to see.
tavsan: Mystic White II pool filter sand. Cost me about $7.99 for a 50 lb. bag and was extremely clean. The fish absolutely love it, I think it closely mirrors the substrate in their natural environment. The peacocks actually hover above the sand and dive in with their mouths just as they do in the wild.
Thanks for all the input.