Is my Sebae dying?

[rogueshadow94]

I need some help with my Sebae. He has not seemed happy since I have bought him. I have had him for about a month now. Sunday he started to look really bad his mouth is open pretty wide. He is not loosing his color and he is still eating. It might just be stress but I would like some other options. Everything else in my tank is thriving and extremely happy. But not my Sebae.
Tank is a 90 gallon 48x24x18
Lights are T5s with a Orbit Current Marine ic Pro
All of my parameters are perfect I just checked them this morning. Thanks for the help.

 

[andrewey]

How old is the tank?
What are the parameters?
How was he doing before Sunday? Sunday decline or was it gradual?

 

[rogueshadow94]

The tank has been set up for over 6 mounts now. He has been declining for a little while. I decided to change the rocks around in the tank and after that he started acting different. He has 2 skunk clowns living in him as well. They make it really hard for me to feed him but he is eating. I don't think he is bleached.
Salinity 1.025
DKH 9
PH 8.2
Phosphate 0
Nitrate 10
Nitrite 0
Calcium 450
Ammonia 0