What’s wrong with my wrasse?

[Vintageblues]

He finally emerged from hiding tonight after not seeing him for 2 days. He was breathing heavily and was mostly immobile or upside down. Is it ich? Do I need to treat my whole aquarium? All other corals and fish look alright. Tested the water and everything came back normal except nitrates were at 20ppm. Temp is a balmy 77 degrees. He is no longer in the tank so my concern now is whether I need to treat my tank.

 

[Humblefish]

Looks more like flukes: https://www.reef2reef.com/threads/flukes-–-general-guidelines.224423/

A 5 min FW dip would confirm that diagnosis: https://www.reef2reef.com/threads/freshwater-dip.248898/