IPhone :: Can Read Mail Without Downloading New

Can I read mail in my inbox without downloading newmail from the server? I would like to be able to open Mail and read an email without it downloading new emails and using up data and battery -I'd rather set it to manually do that. There's a feature to "fetch manually" but either it is not working or I am misunderstanding how it works. Everytime I open Mail it checks the server. I played around with turning on and off Fetch and Push. Seems unfortunate that I might not be able to read an email in my inbox without downloading unknown large emails while traveling where data and battery are sometimes difficult to manage.