How do I know when Ich is gone?

[46GFreshwater]

Hello! I wanted to say thanks to everyone in this forum/community - this has been a great resource for me. I had fish & aquariums growing up but had a lot of misinformation as well. I am re-starting my interest in the aquarium hobby and this website has been great!

I have a 46 gallon aquarium (with Marineland Penguin 350 GPH) that was cycled (fishless) for 2 months before I got my first fish. October 9, I added 4 x Sunburst Wag Platies and 1 x Clown Pleco. Unfortunately I did not quarantine these fish prior to adding to my tank since on October 12 I noticed a several white spots on the smallest + thinnest platy and noted him flashing. There were 2 spots on a female platy as well. I suspected Ich - tiny salt-like specks protruding from fish body.

I wanted to try to treat with high temperature alone and increased the temperature to 30 C / 86 F.

Oct 16 I purchased a 10 gallon tank to use as a hospital tank, since I noticed many white spots peppering the pleco and the smallest male platy had been resting on the bottom in distress for a few days. I moved the sick platy and the pleco to the hospital tank (removed the carbon filter and added a small square of filter media from the main tank). The other 3 platies had no spots and were acting and feeding normally.

I treated the hospital tank with coppersafe per label directions.

Oct 17 - small platy in hospital tank dead.

Oct 22 - pleco found dead in hospital tank after a few days of Ich spots improving.

I have the API Master kit for testing and the ammonia and nitrite were 0 in both tanks (daily testing).

Oct 23 main tank parameters right before my most recent 25% water change:
temp 30 C
pH 7.8
ammonia 0
nitrite 0
nitrate 2.5 (between 0-5 on kit)

I have not seen spots on the 3 remaining platies since Oct 13. The sickest fish were removed from main tank Oct 16.

Questions:
1) If I don't see any white spots on my remaining platies does that mean that Ich is eradicated? Or could they be temporarily immune?
2) I was considering treating my main tank with salt but I don't have a refractometer and I was looking into getting a hydrometer but they seem unreliable on reviews and many would be hard to accurately detect salt at 3 ppt since they are designed for much higher salt levels of saltwater tanks. Thoughts on salt treatment?
3) I am reluctant to treat my main tank with any medicine other than salt at this time - do you agree?

Thanks for your time!

 

[Twistedrider]

To be sure it doesn't come back I would put all the fish back into the 46. Then I would dose it daily with ParaGard by seek SeaChem. You don't have to jack up the temperature it won't stain anything and it won't hurt your bacteria. But it does a great job on getting rid of Ich and is easy on the fish. You can't hide from Ich so if you had it in your big tank you should treat it there. Always quarantine new fish. Good luck.

 

[Delapool]

Generally I would say all the white spots must be gone for a minimum of three days. Under heat treatment a week to 10 days seemed to be suggested (haven't used this for a few years now). With meds you could drop to a half dose if just wanting to see out a treatment period.

Any flicking around the gills where we can't see into very well may suggest it is still there. Some thoughts, interesting topic.