Hi Reed,
I have kept a couple of them. The one that I have now has been in my reef for 11 years. I suppose that you could find one that doesn’t behave, but IME they are as close to the perfect fish as you can find. They are peaceful, hardy, don’t cause any trouble and they are not fussy about what they will eat. I did have a bubble algae problem when I got my Foxface Lo and it took care of it. I had to remove all the big bubbles and the Foxface ate anything small or new. They don’t require a great deal of swimming space, but I think that a four foot long tank would be minimal for their comfort. Keep in mind that they do get fairly large and they like to eat (and produce a lot of bioload). Make sure it gets a wide variety of plant-based foods to go along with meaty sea foods.
Cheers,
Terry B