Umm... Guess I should have included more details. He eats normally, swims normally. The only odd behaviour is that he is always scared and hides a lot. The other chromis, much younger has no signs of injury or "disease". But he does mimick the "big brother" and hides a lot too, except not as much as the big one.
The water parameters were the following:
I just placed him in an isolation bucket with some MelaFix to see if that will help. I had quite some fun to take him out of the QT
. Two nets did help though.
Poor thing, he was so scared when I placed him in the bucket, that he came right up to the surface and then went carpet surfing.
My first sick buddy. Whish me luck. 8O