Generally speaking the Atlantic blue will get around 9" fully grown, so a large tank long term is best. 180 gallon or bigger, 6ft long.
They, like other tangs will eat meaty foods, flake and pellets, but need algae in their diet on a regular basis. So, dry nori algae sheets placed in a algae clip provided a couple times a week will do.
If this is your only tang, introducing another tang latter will end up in a fight, possibly death to the new comer.
It's best to add tangs in multiples at the same time and they should be the last fish added.
Yes this carribean blue tang is a very aggressive fish and very prone to parasites. The vast majority of them succumb within months if you do not properly treat and quarantine all fish before going in to your display.
They do grow rapidly, my 2.5" carribean is now 6.5" 2 years later. They become progressively more nasty as they age and grow. Beautiful fish, however.
Also it's true that adding tangs to a carribean blue adult will be suicide unless several are added together. I would add them while she's young if you plan to.