I ended up choosing a dwarf puffer:
at first he was acting really stressed and i was worried when i went to bed last night, but now he's swimming around the tank looking at everything!
my only concern is that he seems to think that the moss ball i added yesterday is food, he keeps circling it like he is trying to figure out where the opening is
thus far, he has completely ignored the ghost shrimp.. one was sitting next to him, and one was right behind him cleaning away on the moss ball and he didn't even look at them. Of course, he might still just be full from the LFS too..