

Red velvety sploch on amano?
I've been on vacation for a couple of days. After coming back one of my amanos has this red/pink sploch. It looks a bit fuzzy to me. What could this be? I've done some research but I haven't found a clear answer.
Thank you for your help!
Ph: 6.3
Kh: 1
NO2:0.05
NH4:0