I've always been a big Leporanthicus fan. They're all quite active, don't get too large and very striking. I've imported many L240 in the past couple years, but this piece stands out as the most impressive. Perfect finnage, big bright white spots and a dark black background. Current size is about 4 inches.
http://www.youtube.com/watch?v=CJYJEumI9jU

http://www.youtube.com/watch?v=CJYJEumI9jU

stunning