When I first got the fish I did not examine it thoroughly. But after a few days I was watching the fish closely and noticed it. So I guess you could say the fish always had this. And to be honest, I did notice 2 string/worm like objects hanging by the puffers chin. But I never got a good enough look at it. I don't know if they were an anchor worm or not. But I fed garlic soaked food for about 2 weeks and I no longer saw those objects.
The puffer's poop looks normal. I do not see any other signs of disease or illness. But the pics make it look worse than it really is. You have to almost know its there to notice it. It has to be in the right angle too. As far as the color it changes when the puffer's skin changes colors. But the area is always slightly concave. I'm not sure what the problem is. I was thinking a birth mark or maybe a scar as possibilities.