IMO, not all LFSs personnel are fish-oriented, if you find one that is, treasure him/her, there could be a lot of knowledge there, otherwise, it's the opposite: ignorance not acknowledged, just sale-oriented.
My female betta have different sleeping places in the 10gal she shares with a school of young zebra danios. I have seen her resting (sleeping) in different places: supported by the thermometer, supported by a dense bundle of anacharis (planted) or just laying at the bottom in any of three sand-only areas that are "quiet" in terms of water movement. And, until recently, not supported but underneath the upper leafs of anubias barteri (I moved that plant to another tank last Friday).
as for swimming, she enjoys going against the current stream from the
HOB (quite strong); she places herself (as the danios do too) in an open space where she is driven slowly backwards by the current (which is slowed down by the plants) they all do that quite often either by themselves or in company; and other times she just remains around the "quiet" areas (either planted or open spaces).
as for hiding, since she is really curious, gets in/out everywhere (hides so well I have had trouble finding her). I rearrange the
aquascape weekly as I do maintenance (trimming/moving/changing plants, shifting the angle/orientation of the "Chinese-Wall" decoration, piling up some gravel) but keep some areas intact (like a bumpy sand-only area around the right-side front corner behind a bunch of planted anacharis).
as for breathing, she has spent a lot of time without surfacing at all (dissolved O2 in her tank is likely high).
It is quite surprising how many different scenarios can be found/created in a small tank. I didn't plan for any of this to happen, I have just discovered this by sitting around, watching them go their own business. I guess every single fish has his/her own individuality, and that goes way beyond being or not aggressive, reaching certain size, and certainly in terms of inter-species compatibility (other issues like breeding, intra-species behavior, tank requirements, ranges of water parameters, seems to be quite predictable, as far as I know).
Tall tanks are probably not a good idea for bettas, but I am quite certain that they rather have room to choose from than not.
Pepe
Santo Domingo