Thanks guys - yes after looking into glass worms, I found black worms easier to get ahold of. They do like , and eat, these with the quickness of a cheetah, lol... but are becoming more like a sloth when I put the mysid in there. They initially ate the mysid. So now I guess I spoiled them by giving live feed. I have gone from mysid, to black worms, now adding ghost shrimp here or there as a treat. I do not mind feeding the blackworms, as from what I have read- they are the most nutritious- however, they aren't lasting long.
So I think I will buy smaller quantities more frequently, as opposed to my initial thought of buying a larger batch each week. I was told to keep them in the fridge. Any other options?
I have asked- they are wild caught, from Sea Dwelling Creatures. They were feeding - and appeared healthy. There were 3 of them in the tank, until 2 had began to show aggression towards the third, so it had been removed... then I came to the store,

lol
I am still observing the "nip and run" but they stop doing it if I have my camera in hand. I will be smushing the videos together to get something to show what I am seeing, as I have sat there - quietly- waiting, and tried to capture it, lol Darn camera shy buggers

I will need to delete alot of "stand still" footage