when i helped gabe with shipment, tangs always come in rough looking, they stress out so easily. usually after aclimating he would grab the bad looking ones and gently hold them and move them back and forth in the display tank, gently forcing water over their gills(kinda like when you catch and release a big fish). they would usually perk up. but like i said tangs are very sensitive and do not always make shipment no matter how well they where before.