Do you know what your water parameters are?
Is your tank cycled?
Do you feed the shrimp?
Sometimes they get cranky if they are really hungry.
But also poor water conditions can cause fish to be aggressive and perhaps the same for these shrimp.
If you do not have a test kit, do several water changes.
If it's been more than a week since your last water change, do a 25% pwc, then right after do another.
Wait a few to 8 hours and do another and if it seems like the shrimp is calm then do another pwc the next day.
Get a water test kit. If you only have test strips, they frequently become inaccurate.
If you have done you water changes more recently then try doing a back to back water change of a larger amount say 30-40%, then another, 50% and see how the behavior is.
Make sure the water changes are temperature matched tot he tank water.
Check the water temperature as well, making sure it isn't too cool or warm.
If you aren't sure about the nitrification cycle, the article link in my signature will help clear it up and help.
