To be honest, the elegance looks more it's "upset by something", then "not doing well." It is quite closed up, but there is no tissue recession yet, brown jelly, etc. Hope still imho.
Do you check for stray voltage (not just a hand test, but what are the readings with an actual multimeter)? How old are your amm/nitri test kits? If more then a year old, would recommend to get new ones, not API's, and retest.... If the elegance responds to food, feed it, but if it doesn't change, definitely stopping trying to give it food. Expelling energy trying to digest food, is the last thing a sickly coral needs.