Red Coris Wrasse Near Death

Brief description of the problem.
A picture(s) will also help.
PARAMETERS (important)
Temperature: 77
PH: 8.2
Ammonia: 0
Nitrite: 0
Nitrate: 20
Salinity: 1.026
dKH/KH/Alkalinity: 12
Magnesium: 1640
Calcium: 440
Phosphate: Present....Low

Tank size? 90
Estimated total system? 110

Reef, fish only or, freshwater? Reef

Current inhabitants? What and how many? 14 inches fish
Clean up crew? Yes...Florida Cerith, Dwarf Cerith

How long has your tank been set-up? 8 Months

Substrate.
Type? Sand
Depth? 1.5"

Live rock? Yes
How much? 130 LBS
Did you recently add some? Yes 2lbs with Xenia attached

Filtration.
Type? --
Protein skimmer? Yes
Do you wet or dry skim? Wet
Maintenance schedule for filtration? --
Drilled tank/hang on back overflow? HOB
Sump/refugium. What's in it and how much? Sump
Macro? What kind? No

Lighting.
Lighting type? PC
Age of bulbs? 8 Months

Feeding
What? Dry
How much? Few big pinches
How often? Twice weekly

Water change schedule.
How much? Don't do WCs
How often? Don't do WCs
What salt brand? Reef Crystals
Water source? RO for additives

Additives/supplements used? Reef Advantage Calcium, Reef Builder, Epsom Salts, Red Sea Calcium +3

Do you have a ground probe? Yes
What kind of flow does your tank have? 34x

Any additional info you would like to share.... Including anything different that you have done/not done.

There is a possibility is may be reacting to me putting in too much Mg. Possibly. That is the only thing I can think of. None of the corals or other fish are affected at all. I think I raised the Mg 150 to 200 ppm in a 24 hr period. I took a reading, mixed the solution and fed it into the tank (drip over a few hours). Retested a few days later. This was four or five days ago.

Let's get to the bottom of this. Any of the above info that is questionable to you is pertinent to keeping a happy/healthy tank/wallet.

OK, thought I had a dead Red Coris Wrasse. It is weak and breathing heavy. I was able to catch it and put it in my nano. I don't think it will eat. I am thinking a last ditch formalin dip to see if helps. Dip, rinse, back in nano and hope. Whatcha think guys and gals?

 

Possibly. OK, I will for-go the dip. I am going to keep it in the nano just for observation and the ability to get at it if needed. If it gets back into my rockwork in the 90, I will do more damage to the entire system moving things about trying to get at it. It likes to hide. It is a wrasse. It will probably bury itself in a self fulfilling prophacy.

Thanks for the quick reply dude. Appreciated.