Depends on the fish. I used to have a black background with black sand. Most of the fish I had in there I thought would be more vibrant, but they blended in. The Silver Aro I used to have poped, the Pbass would mostly be dark and didn't look as good, Chinese Perch blended in, Jag was dark, JD was dark, Albinos work real well in there, CK and RCK blended in surprisingly, and Dats were ok, GT was good, etc. You pretty much want to go with fish with a high shine or Albinos for them to really pop out. Otherwise, they just blened in, IMO