10g planted tank with a peaceful Betta, a mystery snail, and four otos. I've had the Betta and the mystery snail for close to two months. I've had the otos for about a week and a half. One died early on in my first batch of three. Another died early on from my next batch of three. The remaining for have been doing well, they're active and eating and have nice fat bellies. This one oto has had a spot on his head since shortly after I got him. I had the quarantine trio of meds in the tank when I first got them. I have been doing daily 30% water changes and continued treating with Ich-X. About two days ago I also started adding in Maracyn. I thought the spot was looking better but today it looks worse to me.
Temp is 80°. I raised it slightly from 78°. Parameters are in the first photo.
Here are some photos of the spot progression, if that's helpful. These are going back in time to when I first got him. I should add, he is still active and eating well.