Maracyn-2 Disaster

[TheMirror]

OK, so I have some Silver Dollars and giant Danio's in a 70 corner tank. The fish have been doing fine for over a year, but had developed some pretty significant fin rot. I started them on a Maracyn-2 treatment, following the dosage instructions very carefully. On day 4, all the fish were breathing very rapidly and nosing around at the top of the tank. Tank had become cloudy. Then they started to die, one by one. I tried a 25% water change, which perked them up for a while, but several died overnight.

I thought this stuff was supposed to help, not kill!

What happened here?

Thanks,
-Mirror

 

[WILDER]

Did you increase aeration in the tank as med reduce 02 in the water.