Hi all, I posted about my tank diseases (see "Mystery diseases ruining my tank" if interested) Link below: https://www.fishlore.com/fishforum/...ery-diseases-ruining-my-tank-please-help.html and am trying to treat with Maracyn-Oxy. I have a 10g tank (2 female bettas and 2 corys) with heater + filter (I cut out the carbon insert and am running it without this), and am on my third day of treatment. Sadly, last night one of my betta's head was super bloated and it's normal purple-blue color changed to a very patchy white and dull purple (almost grey) within hours, and then she died - all of this happened since adding Maracyn-Oxy for a white growth on its head. Now my other female betta looks terrible - white streak along side and very inactive. My cories seem unaffected. I'm new to fish diseases - is Maracyn-Oxy potentially doing this to my bettas? Is there another better all-purpose treatment? Thanks!!