Best fish for nano reef?

[FWC]

Watch out though, pistol shrimp love to move sand around and they tend to move any small rock/corals on the sand too.

A Goby/Shrimp pair is cool but I had issues with mine making huge sand piles.

Another one I would recommend is a small Cardinalfish species. Peaceful, cool looking and they don't swim around all over the place.