3 fish dead in 2 weeks and it does not look good for the rest

[sitandwatch]

So I have lost 3 fish in the last two weeks and not sure I can stop the loss of the others.

So far I have lost blond naso, yellow eye kole and yesterday Mr lips(red lip blenny)

Out of the fish remaining
Pink Tail Trigger looks the worst
Clowns second worst
Yellow tang looks ok - some spots
Fairy Wrasse looks ok - some spots
Niger - looks ok but starting to see some issues
Mystery Wrasse - looks great some how

nitrates=0
nitrites=0
phosphate=0
ph = 7.8ish

I am running carbon, and n/p pellets

Since the weekend I have reduced feedings, done a water change, increased flow, did two days and nights of no light.

Added garlic and vitamins to food and directly to the tank

The fish are all still eating mysis, pellets and flakes. Piggy fish(pink tail) loves to eat.

Here are some photos, If you have any suggestions please let me know.

Note quarantine tank is out as I don't have the time and funds to set it up and I think that catching the 7 fish and putting them in a small tank would cause a lot of stress.

Thanks Brian