your tang is gonna need so much more than that to stay healthy, where as the damsel and clowns will most likely be fine... best thing to do is get some green nori and a veggie clip, and put a piece on there everyday for him to graze on at will, daily... in the wild, and along with their incredible metabolisms, tangs eat and pick constantly throughout the day... do not let anyone tell you differently, as too many people do not feed their tangs enough, or their anthias for that matter... i have seen this first hand while snorkling in Maui many many times, and sometimes for hours on end... if your tang is about 4" in length, he should probably be started with a 3" x 3" peice, folded up and put in the clip, and replaced fresh daily, while removing what is not eaten from the previous day... and then from there you can kind of gage what to put in each day... aside from the nori (seaweed), use your judgement of how much to feed of the other foods... if there is still some floating around after a couple moments, cut back the next time...
I feed my purple tang upwards of 4 times a day, on the days i dont give him a 4' x 3" peice of nori... he gets purple, red and green nori on a rotating basis... along with mysis (rinsed thoroughly), spectrum small pellets, and Omega one protein flakes... dont ever bother with brine shrimp, as they offer no nutrition whatsoever, even the vitamen enriched or gut loaded ones for that matter...
sorry i havent gotten a chance to get back to your last pms Tran, i will be in touch soon
and again, feel free to ask anything and i will help where i can...