Shrimp acting strangely

[calble]

Hello, a few months ago I set up a new tank and after waiting a month or two I moved my shrimp from the ecoshpere I got as a Christmas gift to the tank. They seem to have been doing fine but recently on started acting strange. Instead of swimming around foraging for food it seems to hang out one place for longer periods of time and not make any movement. It will periodically move and then stay still for a long time. Also its tail is arched up all the time and the other shrimp aren't like that.

Is there somethimg wrong? Below is a picture.

[Varanus]

So long as it isn't struggling to move or showing other signs of distress it should be fine.