Freshwater disease maybe???
have a 75 gallon freshwater tank. Cycled for approximately 4 or 5 months now after a recent tear down 6 months ago due to am outbreak. Tested 2x weekly. Always 0 ammonia and nitrite and less then 40 nitrate.
I added 6 turquoise rainbowfish and quarantined them prior to adding to the tank. They developed ich upon bringing home and I treated with ich-x. All visible signs of ich have been gone for a week now. Fins and fish look good, swim and eat. There were 6 of them in the quarantine tank total. Quarantine tank is 20 gallons.
The quarantine tank was not cycled but 50% water change daily and dosed with seachem prime daily. They were in this tank for 2 weeks. 1 week after last sign of ich. Started with 80 temp and dropped to 77 the last few days to get them used to my other tank Temps.
I just added them today and I am noticing one of them has a wierd patch on his head (this was not visible at all under the lights in the quarantine tank and I started at them daily). Please see images. 1 also has a dot, small dot the size of a pencil of the same color. It is not cottony or anything and almost looks like an old scrap or soar maybe???
Please let me know what you think it may be and how I should handle it. I lost my last batch of fish due to columnaris and a set up before due to ich. Since then I've read up and learned alot about different diseases but I'm just not sure what this is and I do not want to start dosing random meds.