Hi, My clown loaches have white spot.... (@#@$$@$@#!)

So far, they are the only ones showing symptoms but I will have to treat the whole tank to be sure.....

Now I have this stuff called Ichaid.. it has copper sulphate and malachite green as the main ingredients.... I have read that I should treat at half dose for scaleless fish such as loaches and plecs of which I have both in this tank....(the bottle itself gives me no information)

Will this stuff be ok with my discus as well..... I have made no additions to this tank except for a plant.... tell me I am not peed off.... AAAAAAHHHH!

Please tell me if this will be ok for me to use...if anyone has used it before.