What would cause gobies to go blind?

[ImGood]

I have an orange spot Gobi, have had it for 8 months now.I believe from its behaviour the past couple days,that it has gone blind. I had another one In QT last month.l wasn't sure but suspected from its behaviour it had gone blind . The tank parameters are within recommended levels the other fish are behaving normally. The DT is 400g, 2 ocilaris 2 fang tooth blennies. 2 pajama &2 banngai cardinals 6 line coral beauty ,assessor and neon/cleaner blennies couple conch cleaner shrimp variou snails , 2 urchins,(6 more fish in QT waiting) and various sps/lps coral .
Is blindness something specific to orange spot? What would cause it? The fish was eating well until 2 days ago, hasn't sifted any sand or repaired its burrow . It's in a separate QT at this time I don't want to euthanize it( put in bag , put bag in freezer) its mouth appears empty, not interested in eating when offered .

 

[melypr1985]

Usually if they are blind, their eyes are cloudy or appear mirrored, not always though. If he's blind, then you should be able to put your hand in front of him without him reacting. If you see his eyes moving when something passes it, then it's not blind.

does he have any small red marks on his belly?

 

[stevo01]

http://www.advancedaquarist.com/2010/3/fish

 

[ImGood]

There is no electricity leak or my multi meter is toast

 

[ImGood]

No small red marks, swims clockwise constantly if lights are out,sits still when lights are on only moves if prodded can hold its regular food in front with no response I'm checking out the link Stevo.

 

[ImGood]

Is it possibly ichyophonus? I looked at whirling fish diseas and could only find info about fresh water. I'm starting to lean towards the fungus.