anything interesting that is a night creature. Don't find much fun in watching snails and shrimp ya know, lol
I dunno. the moonlight period is when I really get down to the nitty gritty of looking my tank over. It's when I examine all the rocks and check how corals are doing. It's when my clean up crew is active and i get a chance to check on the pod population. I probably wouldn't purchase something overly active that was purely nocturnal. To each their own I reckon.