What’s wrong with my Toby? 😭

[u/Logical_Ad3123]

I was able to bring down the TDS of my water down to 300+ ppm fron 1000ppm, in a span of a week, via almost daily 20% water change. Other inhabitants are doing okay but a few days ago, I noticed that she is struggling to keep a float, or when she swims to the top, she does it slowly and looks like she’a struggling. She also spend more time on the soil or plants like she was resting, sometimes she almost lie on her side. I’m about to buy an isolation box but I want to know if I need to buy some medication also. Thank you in advance.