Thanks for those diagnosis/suggestions.

While carefully inspecting the other two anglefish I noticed the
smallest (female?) has some slight red puffyness around her gills.

To try and cover all the bases yall mentioned I moved approx. 10
gallons of water out of the main tank into a empty 10 gallon hospital
tank (figured less stress than all fresh water). Setup empty small
whisper filter for some small airflow. I put in some large plastic
plants from the main tank and left them floating for some cover. And
medicated it with Maracyn-Two by Mardel. I couldn't find the other
suggested medications at my local petsmart and tommorow I'll range
further and look for them.

I moved the two sick anglefish, and left the largest and most aggresive
one in the main tank who looks healthy. That should have the effect of
breaking up the two possible males. I prepared a batch of new water
and put it back in the main tank to replace what I took out for the
hospital tank so it effectivly got a 20ish% water change.

I typically add about half a tablespoon of Jungle brand aquarium salt
at water changes. I didn't put a new dose in the hospital tank at the
rate Frank suggest as I didn't know if there would be conflicts between
the salt and the medication, is that a real concern or should I add the
salt as well?

My main tank isn't planted, I'll up the water changes signifigantly as
suggested from now on. That should help the green tank too I'd
imagine.

Any other suggestions or ideas I'm all ears. Thanks for the help so
far and I'll post some pics later as the treatment continues. I tried
to get some of my hospital tank but they are all fuzzy and can't see
much I'll try again in the morning.