plah831, don't worry about it. I am pretty hesitant to add medication usually myself and I've had water changes help a lot before. I didn't take any offense and I don't blame you at all. In addition, the people at my LFS who are really knowledgeable couldn't figure out what was happening and suggested I wait another day which I think would have hurt them even more.
So, to update.
I have 4 out of 6 firemouths breathing rapidly.
No change that can be seen with the tiger barbs and giant danios which seem to be acting normal.
Water parameters check out: 0 ammonia, 0 nitrite, 5 nitrate, 7.1 pH
I got some jungle labs parasite clear, did a 50% water change and added in the medicine.
Two of the firemouths seems to have gotten even worse. They are very dark and yesterday one was having trouble swimming and it looked it was struggling to get to the top of the water. I pulled him out and put him in a separate container with an airstone, some salt, and the parasite clear and expected him to be dead this morning.
However, his rapid breathing slowed down a little and he was looking more active. Today, another firemouth was looking really bad and doing the same thing, trying to get to the top of the water and having trouble so I pulled him out. I was going to put the one who looked better back into the tank but as soon as I put him in the tank, he dropped like a stone and couldn't seem to get very far off the gravel and he was getting picked on, so I pulled him out and put him with the other sick firemouth. It looks like they both have swimbladder problems as well...
So far, they are still hanging in there and I added some KanaPlex, which is a broad spectrum antibiotic to help combat any secondary infections or maybe a primary bacterial infection.
However, I do remember seeing white poop that hung on the fish for a really long time which I've read online could mean internal parasites so I'm hoping the parasite clear does its job.
Here's to hoping that the really sick two don't die, the other two puffers stop puffing and my last two who are still healthy don't get sick.
Thanks for the help and suggestions everyone. I really appreciate it!