hello, I’ve been watching my aquarium and I noticed some grey spots on my submarine a while ago but I didn’t remember whether it came like that already. But now I notice grey spots on the gravel and the plant next to the submarine. My fish don’t have any spots but I noticed their clamped fins. I had a couple of cases where fish bullied each other and their fins were a bit clamped so I don’t pay much attention but now it’s most of the fish but they’ve been acting normal and eating normally. Is it something to worry about? I have 4 guppies, 2 otro cats and 2 snails.
Tank had been around since August and ph has always been 8.2, ammonia: 0, nitrites: 0, nitrates: 5ppm and I do weekly water changes.