interesting....
I have had ich before and 1 tang died and he was a baby, tiny. Everyone else lived, with out a sterilizer. IMO i have good flow in the tank and i think that helped save everyone else... and good feeding.
The one that did die didnt eat as much, he couldnt hold his own against the clowns bullying him.
Oddly enough i had another baby tang that fought the clown back and makes sure she eats alot... she lived...