I used the Spectrum Thera A. Granted, I have no tangs, but all my fish are fat and happy. Jeff, see if you can find some Rod's Food locally. I picked up the herbivore blend and my fish go nuts for it.
Ingredients: Shrimp, Scallop, Oyster, Clam, Squid, Octopus, Perch, Green Nori seaweed (porphyra sp), Red unroasted nori seaweed (porphyra sp), Seaweed, Mysis, Pacific plankton (Euphausia sp.) Krill, Brine shrimp, Frozen red cyclops, Fish eggs, Oyster eggs, Golden pearls (all sizes), Broccoli, carrot, Garlic, Baby Spinach, Selco, Astaxanthin (Haematococus pluvialis), Beta-meal (Dunalliella Salina), Spirulina, Freshly harvested rotifers, freshly hatched baby brine shrimp.
http://www.rodsfood.com/