fish losing color

[mathluque]

I need his HELP

It turns out that today my fish are extremely rare

It seemed that they have stain of chlorine, they have white spots is not itch since the size is very big .

The surgeon hepatus is the most afected but it's not the only one , the flame hawk also seems to be bleached and the lawnmower is extremely weak ( thin)

Already check all the parameters and the only thing that was high , were the nitrates but i realized a water change of 80 lts
my system is 280 lts aprox.

I need the help from all you it is something that have never seen








thanks