Not necessarily! I'd put it in a glass with tank water. Set it someplace near the tank so it gets some light. Then 2 or 3 times a day, dump 90% of the water and add new water from the tank. I've kept anemones alive like that for several weeks until I was ready to put them in the DT. And if it dies, it doesn't disintegrate in the DT water!
That doesn't look dead to me! I have had nems looking like that before and are now beautiful colourful pieces today! They can shrink up very very small if they feel they need to.
Have you got any pictures of the nem fully expanded?