Hey there.
I have 3 platys in my 100L community tank. All is well apart from this platy!
He started with a small mark on his head and it has got bigger and bigger. I noticed another small platy started chasing him a bit I guess cause he noticed an illness but nothing persistent or aggressive..
I've moved him to quarantine about a week ago and done 2 50% water changes . I added some metroplex as someone thought it could be hexamita, every 2 days but there has been no improvement that I can see so far.. if anything it seems more raised on his head than before.
I will add the parameters later as I tested last night and wrote them down at home. But 0 ammonia 0 nitrite. Kind if high GH and quite low KH. Nitrate was a little high but i added some ferts last week and am due a water change.. Planted tank.. The tank is about 2 years old. I test roughly once every 2 weeks and there's been no drastic changes.
Any ideas? Someone else suggested applying methylene blue with a cotton bud incase its fungal..
Cheers