Peacock eels, pimafix, and melafix. Did I just kill my eels?

I think I messed up. I have a 20g tank with a variety of fish in it, including two peacock eels. One of my female bettas began to show signs of an infection, but I'm not confident enough to say whether it's a bacterial or fungal infection. Upon doing a little bit of reading, I found that Pimafix and Melafix together solve most problems, so I picked up a bottle of each last night.
I gave the first dose a couple of hours ago (10mL each). About thirty minutes later I noticed that both of my peacock eels were out in very exposed areas. I thought it was odd but brushed it off, thinking that they might be looking for food. Another thirty minutes passed and I noticed one of them resting on some plant material with his nose stuck out of the water, and the other gasping for breath shoved up in a corner. I thought maybe the water was low in oxygen or something, so I turned on the water pump (I keep it on during the day when I'm gone and turn it off when I'm home due to noise) and then sat down to do some research.
I didn't find anything that said specifically not to use these medications with peacock eels, but I did find some people on random forums saying that they just didn't like the meds in particular (not very helpful). I did find a lot of things saying that peacock eels were sensitive to copper, but I didn't see copper in the list of ingredients on the bottles.
I frantically made a quick bucket of water, added API Quick Start, and scooped the eels out of the big tank and into the temporary one. Aaaand then I realized the water was about ten degrees colder than the other tank. I added warm water slowly over about five minutes until the temperature was approximately at the same level as the 20g tank.
They're still huffing pretty hard, but their breathing seems a little bit easier now and they seem marginally brighter than they were half an hour ago.

TL;DR: I used Pimafix and Melafix with my peacock eels. Did I just sentence them to death? If that won't kill them, will the abrupt temperature changes do it? Any recommendations on how to help support them and bring them back around?

If they live, obviously I'll be doing water changes in the main tank until they're safe to go back in.

For anyone who reads, here is a complete list of the types of fish I have in case any others are in danger. No one else is acting abnormal as of yet:
-Betta
-Corydoras
-Rainbow shark
-Gold zebra loach
-Kuhli loach
-Guppy
-Pleco
-Tetras
-Ghost shrimp
-Snails

I also have an assortment of live plants, but I have absolutely no idea what they are. That receipt is long gone.

Thank you to anyone who reads this. I accept that the eels may be too far gone, but I appreciate any viable input.

Melafix, Pimafix and Betafix don't do a damn thing except make the tank smell like a wet Eucalyptus forest. Salt is a safer option for some issues.

Do a big water change on the main tank and post pictures of the sick fish.

They won't do much as far as showing them ADR/lethargy/dyspnea, but I'll do my best! Just give me a moment.

Colin_T said:

Melafix, Pimafix and Betafix don't do a damn thing except make the tank smell like a wet Eucalyptus forest. Salt is a safer option for some issues.

Do a big water change on the main tank and post pictures of the sick fish.

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Here you go!

Do you have pictures of the sick Betta?

Colin_T said:

Do you have pictures of the sick Betta?

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Here you go. Sorry, she isn't the easiest to get photos on. I first noticed the tail damage a couple of days ago but attributed it to maybe a scuffle with the other bettas or something. I wasn't concerned until I saw the discoloration around her mouth.
Both of the eels are dead.

This thread is the reason I hate meds. Most of the time we don't know what we are dealing with. I am sorry about the loss of your eels. Hope your betta gets better.

itiwhetu said:

This thread is the reason I hate meds. Most of the time we don't know what we are dealing with. I am sorry about the loss of your eels. Hope your betta gets better.

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Thank you. It is really frustrating trusting a company's statement that their medication is safe for all fish, but that's also the risk I took when going over the counter for treatments. I wish things ended up differently for the eels, but at least I can say I tried my best for them. And if I get eels in the future, or if you or I know anyone who does, now we know to caution them about the use of these medications with the sensitive creatures.

kellyrazz1996 said:

Here you go. Sorry, she isn't the easiest to get photos on. I first noticed the tail damage a couple of days ago but attributed it to maybe a scuffle with the other bettas or something. I wasn't concerned until I saw the discoloration around her mouth.

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The tail looks fine but the anal (bottom) fin looks like it is missing a piece. The damage could be from fighting with another Betta in the tank.

The mouth could be mucous covering an injury from a fight or the start of Columnaris (mouth fungus).
If the mouth has been like that for a few days it's most likely mucous.
If the mouth has only been like that for 24 hours or less, monitor it and if it spreads over the next day or two, then it's probably Columnaris and will need treating immediately with a broad spectrum fish medication or anti-biotics.

I would wipe down the inside of the glass, clean the filter, and then do a 75% water change and gravel clean the substrate. Then add 2 heaped tablespoons of rock salt and see how it goes. Keep the salt in there for 2 weeks and if everything is good, stop using salt. If the problem gets worse after a water change and salt, and continues to get worse, then post more pictures and look for medication.