What’s wrong with my fish?

[katonge]

I purchased 5 chromis on Fri. Overnight one died and now a 2nd one is showing the same marks on the side.
I took the dead one to the LFS and he gave me a store credit for all of them but didn’t identify what was the cause. They tested the water and all is good aside from a slight ammonia rise which matches my own testing.
Any ideas?

 

[Earl Karl]

It's Uronema

 

[katonge]

Thanks. I’ll look it up.

 

[BayouReefer]

Look at the post under fish disease and treatment by @Humblefish