Thanks for the help! I’ll have to buy another bottle b/c I used the whole other one when I did the first dose. Should I do it right after the water change or could I wait for a few days before adding it?Great! If you do a water change read the fritz enzyme bottle and dose again. I think i remember it saying you can dose with water changes (at a much lower quantity) and I'd recommend since a lot may have died off in the time between the first dose and the addition of the fish