I'd do a little research on that....ich survives and thrives at 80 degrees.
Fishbase shows 77-86 degrees for Angels. I was surprised because lots of people claim a minimum of 82 degrees. I don't use a heater in the summer and the tanks stay at 78, winter I'm going to set them at 78 this year. My 4 Angels are growing close to an inch a month so I don't think 78 is hurting them :-O