parrot has black on its head

i'll try to upload pics but i just noticed black on the top of one of my jellybean parrots and the other parrot keeps attacking it. any ideas?

Does it look almost like it scaped up against something which just rubbed onto it.

With parrots, it is likely stress marks. Check all your levels (Nitrates, Nitrites, Ammonia, etc). If needed then do the approriate water change.

yea like he's been burned - will do the water change - can parrots be grouped together or should there only be 1 to a tank? this "sick" one is being picked up terribly by the other one and they've been together from day one per the former owner - no clue if I have a pair or siblings or what

Yes you can keep them together. Do you have a lot of hiding places?

think so but the one is becoming aggressive to the dojos too - he likes to fight with his reflection on the tank

That used to happen to my orandas. The black would eat up their wen if it was left untreated.
It always started as a pretty small black wound on their head and over a week or so wound turn into a big deep wound ringed in black. I figured it was a bacterial infection and treated it with salt and some meds from the store.
I had one oranda that had one whole side of his face eatten by this stuff. He looked like the phantom of the opera.

i moved the parrots into another tank and the black is gone - i believe it was stress induced - thanks for all the help - i love this site as everyone helps everyone else - great job members!