A wrasse or basslet/gramma/psuedochromis would be a good choice.
Fairy wrasse (bright pinks and yellows)
sixline wrasse (muticolored)
Royal gramma (purple and yellow)
Fridmani psuedochromis (magenta)
My flame cardinal is very active, he is red with really big striped eyes. He isn't the most beautiful in color but his personality is really cool. He is a very active nocturnal fish, but is seen very readily during the day too. Very peaceful, gets along great with my GS maroon clown. He is very active, always darting in and out of rocks. JMO
HTH..........MCF