I think its ich but not acting like it

[Cardex]

After the heater meltdown killed off the tank I gave it two weeks with lots of water changes before replacing fish I got a school of 11 black neon tetras to go with the 8 Cory cats and a clown loach in a 55 gallon planted tank I was stupid and put the neons in the tank without doing a quarantine then a few days later noticed one of them had a single white spot on its tail fin I started treating the tank with quick cure at half dosage put an airstone in the tank turned the co2 off and bumped the temp up to 83 (at 86 the fish were havering signs of stress) 6 days later all fish are fine and eating have not had any losses or any new spots on any of the other fish however the one that had the single spot still has it in the same place at 83 the spot should have fallen off in 1-2 days is it possible that the ich died while attached and the cyst has just not fallen off or could it just be an odd shaped scar I will get a picture when I am home tonight water is good at 0 ammonia 0/6 nitrates and ph of 7.8 normal for my tap water)

 

[Mlani]

do you have the picture? It may help to see what it is you're talking about.

 

[Cardex]

When I got home that night it had spread out the carbon in over night then changed from quick cure to rid ich + I think the first med may have been out of date was something I had sitting around incase I ever needed it was several years old