I second the pygmy wrasse's. I had a tanaka's and it was shy for about a month but then became very active and would greet me everytime I approached the tank. I had mine for about 4 years before he decided to jump out of my tank w/ lid. No idea how he managed to get out. I found him half dried up on the floor 5' away.
Warning though, they do like dwarf certs and will eat them all.