I am no expert here......BUT I don't think the coloration of the adipose fin matches that of a true Armatus or even a Tat. that Adipose fin to ME looks like a Scomb.
Having owned an armatus the way you can tell if it is an armatus or not is the orange adipose fin. Also the profile of the head is a lot different than other payara. His name was "Raider" because of the little white fleck that he had in one eye. At that time Raider was pushing 11". The new owner KRSwop1 is selling him at the moment. MFKers is you have an opportunity to get one do not hesitate! You will not be disapointed at all. The armatus was the best fish that I have ever kept. My only regret was selling him. Here are some old pics from April of this year:
Like Mr. Ifo already stated the most accurate tell of the armatus is the orange on the adipose fin. There have been some red tails that have the white lining on the edge of the tail fin so that is not always accurate. I think once they get some size they are more easily distinguishable. Mine at 5-6" was very thin and I may not have been able to pick him out in a pack of ten red tails but now at 11-12" I could 100%. Definately a bad ass fish with an attitude.
I tried also to upload the pic but it wont come up. They look like Armatus to me the link is in the other FS post. I am going to drive up Sunday morning and gte a few!
Thanks for trying Huge Ghost. Yea well, if anyone is able to upload the pics I wold appreciate it, they do not come up for some reason. Maybe it doesn't like the filename. Anyway, if not I have links on the other thread.