High Bwompus and welcome to the forum
Bristlenose are probably one of the less demanding plecs you could ever want to buy(+ they look kool)
55 gal is a great size tank to start a pair up, they're quite forgiving as far as water quality is concerned
( neutral water is a good place to start ) and they pretty much get on fine with other tank mates- all though
you probably will get the exception to that rule with tank mates showing them a little aggression sometimes.
Happy browsing and posting.

J