i have play sand and and my laps patterns dont show up at all. i sold another lap and saw pics of her in the new tank with black sand and she looks a hell of a lot nicer. eventually i'll get around to replacing the sand with something darker..
I was having the same issue. Play sand looks good but the colors / pattern on fish easily wash out. I have some small brown aquarium gravel in right now and the fish look a lot better, but I'm not a fan of how it looks. Hopefully the new stuff will solve that issue.







