Cant really tell from the pic what the maroonish colored stuff is around the tentacles but it doesn't appear dead. However LTA's are sand dwelling anemones and really like to have their foot buried 4-6 inches in the sand bed. The best option would be to cut off most of the flow in the tank, dig out an area of sand near the rock work down to the glass, place the nem in the hole and gently fill the sand in around it's foot. Give it an hour or so and then slowly return your flow back to normal. You will know when it is begining to die it will smell horrible and will begin to fall apart.