Thanks Laki and Pitluvs.
Pitluvs, I want to place the tank on my bedroom desk so I can be right next to the betta. I actually do work on this desk so there is no room for a 10g. I thought about the EcoPico but the two extra inches on that crowd my arm (and it has the same volume anyway). Thank you for wanting to bless me with your tanks!
My last king betta was in an 8g halfmoon tank with weird dimensions. The tank was 10"Lx15"Wx18"H, and he had a time getting to the top to breathe.
I'm gonna hope for the best. Worse comes to worse, I'd have to get a cheapo glass 10g from Walmart or put the king betta in the 8g if this tank proves too small (these tanks would be on a stand about five feet away from me. The distance changes the social dynamic
). It'll be high light CO2 injected for plants, so if plants are all I can have in it, it would have to do (or get a second, small betta to put in it