If you are really set on a Foxface, you should go up to a larger tank. A 55 gallon LOOKS big in the store. Trust me, IT'S NOT!
They fill up very fast when you put in 50 or 60 pounds of rock, a couple wave makers, your HOB equipment (skimmer, surface skimmer box for the HOB filter) a heater or 2 in and space for coral. THEN try to shoehorn some big fish in.
Really, people telling you that this fish or that fish won't be a good idea for a certain tank for 'X' reason are NOT being jerks and trying to ruin your day. They are trying to advise you against making a misstep that is easily avoided.