Powder Brown Tang Breathing Heavily and Dose not want to eat anything

[Axel33]

Not sure what is going on with my powder brown or what to do. It's been 5 days since I bought it from a wholesaler and dose. Or wanna go to eat food or any foreseen food. He's not even nipping on the rocks.

Occasionally he is going for a swim. My other fishes the powder blue and blue tang are swimming and eating frozen food and nori but not him. I also squeezed some garlic and add a few drops to the frozen food but did not help.

The quarantine tank size is about 17gallons, salinity 1.023 temperature 78. Any ideas on what to do with him?
Here is a video with more explanation
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[Axel33]

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[Sk8r]

Flaring gills may mean parasite. Ich is most likely, followed by flukes.

 

[Axel33]

After a week in the quarantine tank, i moved him to my 120 g tank. Now I see him going and chasing my powder blue and also nipping on the rocks. I did not see any form of ich or other parasite. Currently, I am adding some prozi pro, to the food that I am giving to the fishes as well to the seaweed clip.

I think he did not like it because it was in a small tank but it seems being in a bigger tank is happy.