Hello; OK again. So you did add salt and the malacite/ formalhadhyde? May I suggest some water changes to dilute the salt and other and to try the 90 degree heat treatment.
Also if you do not already have them, add some bubblers.They help keep enough oxygen in the water. Warm water holds less O2.
Good luck
Originally I added salt and heat, which seemed to kill the ich. Then when I changed some fish around afterwards, I discovered some spots on my GT, and decided to take the direct medicine route.
Halfway through the medicine option, I really hate using chemicals like formaldehyde etc; feels like the lesser of two evils, formaldehyde being bad for the fish, and 31° temp also being bad.
2nd half of treatment is due Monday, then I'd be doing a large water change on Wednesday.
Unless it's safer to raise temp to 30° and just do a large change just now to dilute chemicals.
Con.... Your number one issue is trying to change stock while already experiencing issues with disease. I feel like it was just last week that you reported you had ick in your Oscar tank, and now you have moved these fish out and brought new fish in with a load of medicine and treatments in between/before/during/after... Next time you have 'party induced ick' try treating the tank to a state of stable health before switching stock, and worrying less about starting a thread about nitrate levels in Oscar tanks (as a long term... Monitorting thread) in the mean time. Any tank with this amount of flux is bound to crash, hard.
Chill out, nothing is going to change within hours. You were probably well on your way to fixing an issue when you decided to dump meds and switch stock.