You will know if your anenome is dying because it will look like it is disolving in the water. Mucus will be dangling off its tentacles and it will eventually shrivel to nothing. Just keep the water quality good and the anenome should be fine. Good luck with your anenomes and let me know how they are doing. I would want to start with something a little less temperamental , seeing as it is my first time with corals.
Soft corals require extremely good water quality.
It is best top leave soft corals where they are. Let them establish themselves on the rock work so they can filter feed in a consistent manner. The two most common and available soft corals are Simularia or commonly known as Cauliflower corals and Sarcophyton or commonly known as leather corals. Sarcophyton species will propagate actively in the aquarium and push new offspring out at the base of the mother coral. Even though soft corals contain algae, they extend their polyps at night to capture small particles of plankton.