Amano Shrimp sick?

[spiketooth]

i have three Amano Shrimp in a 75 gal tank. one of them is turning black and is not active. the shrimp hs been sitting in one stop just moving there back legs.
Picture of the active one

the other one

 

[spiketooth]

Anyone?

 

[The CodFather]

How long has he been black like that?

 

[spiketooth]

Two days now, what levels are good. Ammo 0 nitrite 0 and nitrates between 15-20

 

[The CodFather]

And he just turned that color? He was clear before? Is he out in the open alot in your tank or does he hide alot?