I'd acclimate the little guy, unless you already have ponies in your tank, however, most here would chose QT. Instead I'd give the ponies a fresh water bath before acclimating them to the tank.
Personally, I would FW dip him and then put him in a QT tank just to be sure there are no issues and to be sure he is eating properly. Much easier to observe feeding behavior in a barebottom tank than once in the display.
Tom
