At what temperature should monkfish be prepared? At what internal temperature should you aim for monkfish to be properly cooked? According to this recipe, it should be at 145F (63ºC). Does anybody know a temperature chart for fish in general?

FYI I just found this and this reference.
To be perfectly honest with you, in all my years of cooking in kitchens I never took the temp of the fish.  It was always by feel and look.  Yes, I know that the gov't has guidelines that say 145F for fish but really when it comes down to it, if you have an 8oz cut of salmon/cod/monk in the pan, sticking an instant read into the middle won't do you much good.  (Caveat: If it was a salmon Wellington I would shoot for 130F as it's a fully enclosed package that you can't feel for doneness)

The thickness of the cut will make a huge difference in when you should pull it out as you get post-oven cooking during resting in which the heat continues to heat the core of the flesh up to a final cooked temperature.  That's why most chefs will take the roast out at a rare measured temp when they are shooting for a med rare serving state.

If your question is what state should monk fish be served, IE  med rare (like salmon) or rare ( like tuna) then I would say med-rare is your best bet.  Over cooking is a bad thing for monk fish and it goes from a lovely moist state to dry nastiness really quick.  A nice way to cook it that helps to give you a little move wiggle room when cooking it is to wrap it in Parma ham (prosciutto).  The little extra wrapping tastes great but also gives you a little bit of buffer as you get close to that magical temperature of doneness.

Hope it helps.