A Shrimp can't cause that kind of damage. The anemone is not healthy and is overly sensitive to being walked on.
Are all water parameters in range? Have they been stable for the last couple of months? Salinity(range 1.022-1.026), Temperature(70-80), Alkalinity(7-11 dKH), Calcium(350-500 ppm), and Nitrate (<30 ppm) are the most critical parameters that we have the ability to measure.
Is AC being used? Activated Carbon is a must for all reef aquariums.
Water changes? 10% monthly is good.
This anemone could be the first to go with the two other anemone's health soon failing if water quality is indeed poor and not improved soon.
What other coral are in the tank? How are they looking?
Fish? I once had a Maroon Clownfish that was too rough with it's host anemone, causing the anemone to shrink and lose tentacles over time.
Aloha,
Mark
Edited by Mark Peterson - November 24 2015 at 8:03am