I buy Nori from the Asian market, and cut each sheet into 4 pieces. (4X5 approx.). I feed one piece a day. It is usually gone within 5 min. I have 5 Tangs and a Foxface. The Fairy Wrasses and Longnose like to nipple on it as well.
In addition to the Nori, I feed about 2 cubes of frozen food, and a meal of flakes.
Fish look very healthy and active.
Am I underfeeding?