Platy Troubles Again

[Jenn.B]

Ok, so about two months ago one of my platies was swimming funny, then he got better after a week of melafix. Now I found him stuck between the breeders net and the side of the tank. I'm not sure how long he was there, but it wasn't more than a day since he was out when I fed them yesterday. The problem is, he is extremely skinny (he was thin to start with because I believe he was a product of inbreeding, but not anywhere near like this), when he swims it's a struggle and his tail is always lower than his head, and he can't swim for more than a little bit before he crashes on the bottom. I put him in a spare breeders box to keep the other fish from bugging him and to keep him somewhere where I can find him, but is this treatable or will he die?

 

[Fuzz16]

What are your tank parameters?
First thing you should do whrn a fish is sick or dies in the tank is do a 20% water change. Dont treat a tank unless it is a last resort. Water changes are a lot better than medicating

 

[Jenn.B]

I did a water change yesterday (the day I found him), and treated the tank because I had luck with it last time, plus I has been treating it anyway because I had added a new fish and I don't have a QT.
PH: 7.0
Ammonia: 0 mg/l
Nitrite: 0 mg/l
Nitrate: 25 mg/l (which I know is high, and I'll do a WC tomorrow to fix)

 

[Fuzz16]

You dont treat a tank when adding new fish, its prob more stressful to do that

 

[Jenn.B]

I had been told since I had no way to quarantine the new fish before introducing them to my tanks, treating the tank with melafix would substantially lower the chances of introducing a disease or parasite to my tank. But thanks for the info, I won't do that anymore.