LTA In Trouble? Quick help appreciated!

About a week ago I rescued a Long Tentacle Anemone from my daughters bf 10gallon aquarium that he had just set up a week before that. I really never intended to keep a nem and my intentions were to take it to LFS that weekend. Well within a couple days it's color had come back and it was filling out, by the weekend it looked real good. I like it so decided to keep it. For most of a week it stayed in on spot with it's foot buried. Last night it moved to the glass and now tonight it's hanging upside down holding on to the glass with half it's foot. It's color is normal and the tentacles are all inflated but the side of the foot that isn't attached to glass has a huge bubble on it that inflates and deflates. I've been feeding it mussels and deli shrimp pieces every other day.
Params are: temp. 76.6*, sg 1.025, ammo 0, Nitrite 0, Nitrate 0, Alk 10 dKH, pH 8.2, Calcium 480, Magnesium 1340 mg/L
I seriously don't want this thing passing on in my tank, that's why I never intended to get one in the first place, but I got attached to it in a short time.

 

Lighting is Nova Extreme Pro 6x39 watt T5HO with brand new bulbs. 3 ATI Blue+, 1 ATI 12000k Blue Special, 1 UVL 75/25 White Actinic, 1 GE 6500k full spectrum.

 

Probably should mention that depth from fixture to substrate is only 16".

 

I hope I'm just being paranoid. It moved down from the glass and attached to a flat rock shelf. It's color is good and it's folded down to protect it's foot so I don't know what is going on with it. I don't want it to die but am real skeptical on leaving it in there. I hear they can nuke a whole tank when they die and that seriously would not be good. My LFS won't take it because he didn't sell it originally + it may be ill. Anyone have any experience with a dying nem they'd like to share?