PLEASE HELP asap

ok i have something very very wrong with my tank last night just ich today one dead fish that looked perfectly fine last night. i did a small water change last night this morning everyone is breathing super fast and my blu tang is very pale i am wondering if i put them into a 5 gál pail of fresh new salt water with heater and filter will that be ok till i get home from work tonight ? please need to know asap it would be blue tang singapore angel majestic angel in pail all about 2-3in in size i want to save them