Honestly, the advice of 2" per gallon came from members of the Silicon Vally Aquarium Society, so I do trust their advice. =/ It's heaps & heaps better that she is keeping her fantail in a 10g, as opposed to the majority I have seen being kept (usually in multiples) in unaerated, 1-5 gallon bowls. Being a Betta lover, I understand, and I would love to see everyone keeping their Bettas in 2.5-10 gallons each. Do most people? Not at all. And I'm happy seeing people keeping their adult Bettas in 1 gallon, even.

Iilo (Erica) , if you are worried about Ghettoblaster out-growing his tank, you can always exchange him for fish that you're more comfortable with. For instance, you could get a couple male Guppies and 4 female Guppies... I love guppies! Or Platys, or Swordtails. You can keep several of these in the 10 gallon together peacefully. (just keep the 1":1 gallon rule in mind). I really like his name, btw!!! ^^