Ich Infestation

[Diablofish]

My Oscar fish that i've owned for about a year now has come down with ich. I've taken the precautions necessary at first sighting. I'm using Quick Cure medication, 1 drop per gallon. So far i've done 2 treatments now because this is the 2nd day but i'm not 100% sure if i'm doing this correct. When i take out 25% of the water and add 25% more, do i only add the treatment for the water i'm adding? And also i'm noticing my fish is lingering at the bottem of the tank a lot today even though he has less spots then he had yesterday; is this normal? Help would be appreciated. Thank you

 

[WILDER]

You only add the correct amount of med back to water removed.

Do you add the med every day as never used the med.

If you add the med everyday and you are doing water changes. Just add the 1 drop per gallon back again.

If you think you have overdosed, do a water change to dilute the med down.

Is there plenty of aeration in the tank.
Does the fish look pale or darker in colour.
Are his fins clamped to his body.