I have three of them, two females one male. The males have the orange head. I do find them to be very hard. They are fussy, slow eaters, because they like to chew their food and spit it out, chew again, etc. Not a good thing to do when there are other fish that like food. They ship badly and they don't like changes. And they need lots of food, if you get one that eats cause most of them don't and die very soon. They are peaceful and shy, not a good fish for a fish only.
I have 7 tamarins in a 1000g peaceful reef, and I feed 20+ times a day.