Ultimate bettas (experts at betta care etc.) gave me the idea and okay to go ahead with it. The website you saw is incorrect.
No offense to the people on UltimateBettas, but I would hardly call them "experts at betta care." I was a member of that site for a while and saw many people given poor advice regarding their bettas (the one that is burned into my memory is the person who was adviced to have a 7-8 female sorority in a 14gal tank...when I suggested that what they were advising was probably not in the best interest of the person asking, not only because the tank was too small, but the person was a brand new fishkeeper and honestly, sororities are best left to the very experienced, I was flamed relentlessly and treated incredibly rudely). I would not trust ANYTHING I read on UltimateBettas, quite frankly.
This is directly from the IBC website:
"Betta channoides can be housed in pairs, species tanks, and community tanks. Pairs can be housed in a 10 gallon tank, groups should be housed in a 20 gallon tank or larger. Pairs should be given cover such as caves and plants. In a pair or species situation it is possible that fry could be discovered in the tanks. For best results remove a brooding male."
Betta channoides
I only found ONE betta channoides for sale on AquaBid and that SINGLE fish was $20 PLUS shipping from Thailand (generally about $40 or so).
I just went through your thread on UB and, to be honest, no one actually answered your question about how many males you could have in a 10gal. That being said, all the info I read on them states they get anywhere from 3-4.75" long...that's HUGE! That's bigger than the "king" bettas you see at Petco. That's as long as my almost adult angelfish! I couldn't imagine the strain on the bioload from more than two fish that size in a 10gal, not to mention the fact that they're so big, they won't be able to get out of each others sight very much.
Why would you want to risk so much with such expensive fish when, to be quite frank, you've managed to somehow kill every other fish you've owned, even the hardy ones. I don't say this to be mean. I'm just trying to get you to think about what you're trying to do. Also, are you sure your parents are going to let you have such expensive fish? It doesn't sound to me like your mom likes you having a tank in the first place.
Please, please, please think about what you're doing before you rush into something like this. I know you're eager to upgrade to "difficult" fish, but I think you need a lot more experience and a lot more of a solid, mature head on your shoulders before you attempt the more difficult fish in the hobby (and as MK said, ANYTHING that is wild-caught is much more difficult than tank-raised).
This is all just my two cents and you'll probably ignore it and get all upset over what I've said anyway, but I had to tell you what I think about the choice you're considering making.
Oh, and what everyone else said is TOTALLY true...the bigger the tank, the easier it is to deal with. My 55gal is almost self-maintaining. My smaller tanks (the 10s, the 9, even the 20gL and 18gal) are much more work. The parameters tend to stay steadier in a big tank and even if there is a fluctuation, it isn't nearly as drastic or extreme, and the consequences aren't nearly so dire, as it would be in a small tank. This is the experience of someone with NINE tanks up and running (including one reef tank) at the moment, ranging in size from 9 gallons to 55 gallons (and I'm planning on adding two more tanks in the near future...a 2.5gal planted shrimp tank and a 6gal dwarf puffer tank).
