long spine vs LTA

[61scout80]

i rescued a semi bleached long tenticle nem from petco last weekend, all week long he was open, coloring up and eating from day one. i came home from work yesterday to find my long spine urchin sitting where the nem used to be. the nem was shriveled up and between 2 rocks. i can only assume the long spine wandered into the poor nem.

can an anemone live through this? how long should i give him before calling it quits? when i left for work this morning he was still all balled up....