Please help. My platies died/are dying from a disease!!

[FishPlanet]

So, All the platies that I have had died from a disease and the 1 remaining is dying from it! The symptoms are: Super skinny bellies, labored breathing, not eating, and arched backs. There are no worms sticking out from what I could see. The only adult platy I have now is dying from it. And, some of my females died from this disease after giving birth. Please help. The only thing that I have added recently are live plants from the co-op. TIA

• pH 7.8-8.4
• Nitrates 10 (I am doing a water change today)
• Hardness 300
• Nitrite 0
• Ammonia 0
• KH/Buffer 180
• Water Temperature 84

[Colu]

Sunken belly and weight loss and rapid breathing it could be wasting disease but arched back could be caused by a bacterial infection can take a picture in the meantime i would treat with Fritz Expel p as it's a 24hr treatment then a  water change then retreat once a week for next 2 weeks after the first course of fritz expel p I would do a course of kanaplex to cover against any possible bacterial infection @FishPlanet

Edited December 9, 2021 by Colu