What is wronge with my shrimp

[i love fish]

On sunday i bought two blood red shrimps and one of them has a brown spot on his tail and another one near his head.What should i do and how long should i keep them in my Q.T.

 

[sepulatian]

The shrimp only have to be there for three weeks, and the spots will be gone with the next molt. Be sure the SG is 1.025-1.026