So last Friday I purchased 6 cardinals and 6 black corys and in the next two days I noticed the cardinals had white spots on them.

I started medicating the tank with esha2000, Esha exit and Esha gdex all together, followed their dosage calculator. They say these meds are safe for corys and plecos. Today, on the third day, I noticed the tetras have less spots but I found 4 of the six black corys dead. One is alive still but cannot find the other...

The tetras still have spots on them so not sure of what to do. Keep dosing Esha exit for a couple of more days? I thought I had kanaplex to feed them with but I don't...and not sure which other med is appropriate. Obviously I am sad the corys are gone but not sure of what to do so I won't lose more fish, get more corys and heal the others. I loved my black corys and I am so sad and confused...check the parameters, all fine.. no water changes so far as manufacturers say it is not needed. Heeeeelp! I feel I killed them ?

I am posting a pic of my tetras to see. I think they have some improvement but not much. I appreciate they are moving so fast it's hard to see what is going on. The two last pics are before and after 3 days of Esha exit etc

Cories can be sensitive to medication so using three at once may be too much for them. For a clear case of ich, only Exit is needed. I would discontinue the other two meds, and if you haven't already, add extra aeration until the course of medication is complete.

Hey thanks for the reply.

Well 5 days of Esha exit and still spots. I am lost now don't know what to do.

Raise the temperature do a large water change and try again after a few days? I heard of stress ick as well that does not respond to medication ?

Stress can trigger Ich, but it's still the same parasite, so it should respond to treatment. I would do a large water change and then restart treatment.