Tangs should be fed algae based food, they are herbivores.
To make homemade food:
From the grocer~ whatever is fresh, blood free, oil free...such as
clams,scallop, squid, shrimp, some nice white fish.
From the LFS~ cyclop-eeze
sweetwater zooplankton
spirulina
Any Ocean Nutrition formula
Piscine mysis shrimp
garlic xtreme {or fresh garlic}
Zoe
selcon
Liquid life zoo & bio-plankton
Golden pearls~ all different sizes if available in your area
Process in food processor or blender, put into freezer ziplocs, push down & lay flat in freezer. The more ingredients the better.