Hmmm, yes this is now bringing back memories of when I dosed my Discus Tank with Flourish Excel and my Discus swam right into it when I was tipping it into the Tank, they came out in Whitish Marks, was damn lucky I didn't lose them, I think.
Had been full of the Flu, and feeling dreadful, obviously wasn't thinking straight, so measured it and Tipped it straight into the Tank, my poor Fishys weren't Happy :oops:
Did a 50% Emergency Water Change the next morning, they seemed to be fine by that night, thank goodness :bounce: