Black tails on Peppermint shrimp

[trainfever]

I have 5 Peppermint shrimp in my 45 and I noticed that 2 of them have black tails. They werent black when I got them. Does anyone have any idea why they turned black?

 

[pagoona]

My 2 peppermint shrimp also have black tails. I don't remember them being black when I first got them, and that was less than a week ago.

 

[trainfever]

anybody?

 

[trainfever]

^^^

 

[trainfever]

where are the experts when you need them?