I have had similar issues with an ultra gold torch that did't make it. I had it in the same area as my toxic green torch and it always seemed to struggle. They never came in contact but no matter what I did it just wasn't happy. When I got it, it was just starting to form a new branch and wasn't fully extending. But as the weeks went by it would only partially extend at random times. I tried moving it around, and it just didn't recover. Ultimately it sucked in and stayed like that for nearly two weeks only partially extending in the first few hours of light, then one day it was gone, having bailed on the skeleton, I found the flesh up against the rock.
As for feeding, mysis is good, but I found that I spent way too much time defending the corals from the fish, so they could actually get to eat instead of having the food picked out. That's when I switched to Reef-Roids, and have had amazing results with it. Since switching to it not only do I not have to stand guard over my corals so they can eat because the fish ignore it, (except for the fire shrimp and his favorite Acan) and all my corals including a bleached fuzzy mushroom (that's slowly getting its color back) are all very fat brightly colored and are growing fast.
To use Reef-Roids or similar type of food, mix about a 1/2 a tsp in a small glass or cup with a little tank water and make a thick slurry with it. Shut off the pumps and using a curved tip dental syringe dispense a small amount on each coral polyp near the mouth. It will take a little trial and error to get the water/food mix right, and you might have to snip a little off the tip of the syringe to make it easier to feed them. Repeat this every 2-3 days and you will notice nearly all your LPS will start giving a near immediate feeding response and open up and suck in the food. If you have any mushrooms, Yumas, or Ricordea they will fold up on themselves forming a ball to eat. It's really a neat site to see. It may take about 10-15 min for all your corals to eat, the food. For zoas, galaxia, and other multi small polyp colonies just press the plunger a bit harder to disperse a cloud of food over them so they will pick up the particles and get to eat as well. Once done kick the pumps on and let your skimmer do the work of pulling out any remaining food and coral mucus that may get released into the water column.
