Please help my friend's fish

[StartingATank]

So, I know this isn't really fresh water site, but I was looking after my neighbors fish while they were gone, and he asked me to go over there every week to make sure his automatic feeder was working, and it was. Fish are the glofish tetras and longfin tetras. First time I looked about a week ago everything was fine. Fish were normal, swimming fine, eating, and breathing normally. But, today, when I went to check on them, all the fish were eating normally and swimming normally, but this green/yellow one looks really thin, breathing very quickly, and not eating. I am worried for this fish, as I don't want my neighbor to come home to find a fish dead. They come home Tommorow.

Numbers that I know of:
Ammonia - 0
Nitrites - 0
Nitrates - 60
PH - 7.4
Chlorine - 0
Hardness - OK, don't remember numbers
Alkalinity - 40

 

[smitten with ocean life]

oh yeah, he doesnt look very good. im sorry. i wouldnt want someones fish to die on my watch either! #fishmedics

 

[Fish Fan]

The other fish look great, so this maybe just all the time his genetics gave him. Good luck here!

 

[Sharkbait19]

Glofish aren’t very healthy to begin with. A lot of poor breeding and being treated like and sold as decorations doesn’t help.
Those nitrates are way too high and likely a contributor. Ideally you want to keep it below 20 in FW, with as close to 0 as possible being the goal. A lot of chronic issues tend to pop up in dirty water, and most diseases are only aggravated. Increasing water changes (and adding live plants) will help.
This one could be being harassed by the other tetras and starting to thin out as a result of being pressured out of food. I’d expect to see more fin damage in this case though.
Lastly is microsporidians - commonly called neon tetra disease. That can certainly make a healthy tetra quickly look like this. It is terminal, but you can stop it from spreading by removing the sick fish before it dies. The disease only spreads from the tankmates eating the dead fish.

 

[StartingATank]

I am trying to convince him to get live plants, and I think he will do it soon. He doesn't do water changes, even though I have encouraged him to do them. The only time he does is when he needs to clean the tank, in which he just vacuums the gravel and replaces the water this way. They are getting home today so maybe I can communicate with him on it.