Pic of white patches on my trigger... Advice?

[Firefish]

Hi guys-
My 4" trigger (Chuckles) has just started showing these visible white patches within the last few days. Any advice would be much appreciated...

Water is in good shape. Zero NH3 & NO2... NO3 is around .5ppm - 5 gallon water changes every week for the past month or so (72 gallon tank) SG = 22 & temp stays around 78-80*

He's been in the tank for about 4 months. He eats everything I put in there (including the red plastic nori clip, which for some reason he doesn't like:rolleye1: ) I feed him a couple of silver sides once per day.
He's breathing fine, swimming well and otherwise gets along well with the other fish.

 

[TerryB]

Do you quarantine all new additions prior to adding them to your display tank? When was the last addition? I would start with a large water change using well aged and aerated saltwater (mix minimum of 24 hours). What are the foods you are using? What are the other fish in the tank?

Terry B

 

[Firefish]

Thanks for the reply Terry...
He was the last addition to the tank. I don't have a second system to use as a quarantine. The lfs where I bought him has always had quality fish (Uncle Neds). They had him for months before I bought him ...always in great health.
I'm not sure a large water change would do any good to be honest. Like I stated above, the water quality is pretty good. All water in the tank is ro/di and I do 5 gallons per week right now (1/3 per month). I have a berlin skimmer running 16 out of 24 hours and about 150lbs of lr. The other fish all seem fine also, which would lead me to believe that the water is ok. I do have a 155 gallon that's been up for over 6 years but there's a lot of coral in it so throwing the trigger in there is kinda out of the question.
He's been eating the same food for months, silver sides / large krill / brine / flake and any fingers poking through the surface

The only other fish in there are the Naso Tang, a couple of clowns and a damsel. All fine & happy as well

I do have a spare 5 gallon in the basement but no equipment for it.