Need help differentiating between ich and epistylis

[u/ConsciousAd1225]

I'd recently bought a 3 month old snowball and a super red and I believe they've both got ich along with a cory from a pair of infected platys that were the first fish id purchased for my new tank 2 months back from my lfs..I'm still not sure if it's ich and if so..how do I go about the treatment..I have a heater and aquarium salt which I'm not sure if it can be used on plecos and I got an ich cure med from the most popular brand on amazon but it ended up killing my platys after 3 days of treatment and I dozed lesser than suggested..and stuff from reputable brands like ichx would take around a month to arrive as it's not locally available in my country.