Not sure what this white stuff on my peppered corycat is. I added three new peppered cats to join my existing pair that's over a month old. One day later my oldest and largest cat has this growth on its dorsal.
First day pic
To be safe I started adding daily 10 mL of Seachem Paraguard to my 20 g to treat the whole tank. I lost one corycat (one of the newbies) to an unknown issue, it had no white spots on the second day.
Now a total of 4 days later, the growth on the oldest corycat is half the size and no longer as fuzzy as the first day. The rest of the tank is doing well, showing vibrant colours and no stress.
4th day pic
What is this growth? Did I treat the tank correctly?