dis is interesting..watch japanese conduct survey to see how heavy a fish can a cat handle...dun worry it's not ornamental fishes, it's those dead fishes u can get from the market for yourself to eat.
http://www.youtube.com/watch?v=G_7n34fiB1Q
If I remembered correctly, the 6 line wrasse is one of those fish tat take the worm for dinner. But keeping this fish will pose another problem of compatibility with other fishes.