Is my chocolate tang sick?

[big man]

When I first got him he was very active and eating but just in like 2 days he has not been eating and became lazy on the bottom but somtimes swim around the tank and he sometimes rubs against the rocks once in a while.
And I have noticed one white splotch on his body picture attached.
So his he sick or is that just a a scab

I also I two clown fish with him but the clowns are not aggressive towards him

Parameters ammonia 0, nitrites 0 nitrates 0 salinity 1.022
Tank is a 50 gallon

 

[reefz]

How long has your tank been set up? Ph, alk? Hard to tell by the photos, but looks like a bacterial infection. If you don’t have corals, I’d run melafix if you can. Also work on nutrition, i recommend soaking whatever your feeding in vitachem

 

[big man]

The ph is 8.1 and tank is like 3 weeks old and I have no corals. for the melafix do I can just pour it into the tank
heres another image

 

[vetteguy53081]

Looks like a blemish from Post injury. I dont believe bacterial. Keep an eye on it at this point. It should improve- Not worsen. Color will be faded for a couple of weeks if post-injury
Assure it gets proper diet. Best foods are :

-Spirulina brine shrimp
- LRS Herbivore diet
- mysis shrimp
- small plankton
- Nori seaweed basted with garlic extract
- Hikari Marine cuisine
- Formula 2 flake and frozen
- Hikari veggie marine

Add selcon vitamins to the foods 2-3X per week and on alternating days, garlic extract for stamina and immunity health

 

[Reef AquaCult]

Looks skinny and malnourished you need to get it eating quickly try foods from vetteguy