My friend's angelfish used to sleep out in the open when the light was off... just floating in mid tank... so it sounds to me like yours may be sick. I've seen other fish act like you describe. I lost my gold gourami after he was acting that way ... he ended up being very weak and got stuck to the filter intake.... he eventually died of Dropsy. I would definately put him in a hospital tank and medicate him.
PS. my betta sleeps underneath his tree trunk ornament, and my flame gourami and female betta sleep in mid tank. (and lol they do have a "far away" look on their faces)
2 gallon with 1 male betta
29 gallon with 2 paradise fish, 3 black tetras(pink and blue variety), 1 sailfin molly, 1 pearl molly, 2 corycats, 1 oto, 2 female guppies.