White spot on purple tang

[AlexT1981]

My purple tang developed 1 white spot near the tail and some discolouration on the tail fin

.anyone experienced that?
Also youtube upload:
Water param:
Salinity :1023
Amonia 0
No2 0
No3 ~ 20 water change today + chemipure blue 2 days ago
Fish is eating very well nori+ mysis with lipovit and lipogarlic& instant ocean formula 1

 

[Jay Hemdal]

Pretty large to be ich. Could it have snagged its caudal spine on something?
Jay

 

[AlexT1981]

Pretty large to be ich. Could it have snagged its caudal spine on something?
Jay

I think ich would start with a lot of white dots not one( as far as i understand). He swims normally and eats lime crazy

 

[AlexT1981]

All is ok after 2 days. I did feed frozen with lipovit and lipogarlic /2 water changes . The white spot disapeared.