Since I bought my Yellow Tang last week I have had a piece of Romaine Lettuce clipped in the tank as a supplement. It was completely ignored by the Tang until yesterday. When I came home from work only the "skeleton" of tougher parts of the leaf remained. My kids reported that the tang was eating it non-stop. I have yet been able to get the tang to eat any flake or frozen food I have provided. It does graze pretty much non-stop on the live rock. Even before it started eating the lettuce its stomach started filling out nicely so I knew it was getting enough to eat. I do need to make a trip to an Asian market to pick up some nori which is dried seaweed which is supposed to be better for the tang than lettuce. In the meantime the lettuce will do.