The more I research, the more I'm thinking this might be camallanus.
This morning it appeared as if he had eaten last night finally which is a good sign.
He also pooped and it otherwise looked relatively normal with a white-ish coloration to it, but it was not really stringy and solid white.
The one thing is I have not yet seen any of the red worms associated with camallanus. I have read that they may stay internal but most of the pictures I see with images of fish infected with camallanus show the protruding red worms or red worms in addition to the swollen vent.
Payara are a very delicate fish and sensitive to medication so I have been taking my time and not reacting irrationally or without first being certain of the identity of the problem and the proper safe treatment. But I do not want this to worsen any further.
If anyone with some experience with this can give me a little advice both my fish and I would be truly grateful.
Thanks,
Reed