Well, the update ..
I went to the local fish shop to get some advice. They recommended Melafix. They also tested my water, same as my own findings. My water is good.
I added the melafix and within minutes the fishes condition worsened, he couldn't breath. He was already in that state, but suddenly he was lethargic, unable to get to the top for air, laying on the sand. 1 hour later, he died.
Now the healthy clown is hiding under behind some LR
. When his buddy passed, he hovered over him, and at one point laid next to him. I actually feel bad for him, soon as I know the tank is healthy and it was just him i'll be replacing him. I am also contemplating doing a 25% water change, cause now i really dont know if I trust this product.
I really dont know what to say, my first shot at salt water fish and so far not so good.