Lauren said:
My general devil advocate responses:
1. the roots will act as a filter, and other filtration can be applied
2. not necessarily. In a home with a relatively stable temp it could be okay.
3. sponge filter can put air into the water, and take care of #1
4. drop betta pellets in once a week
5. tubing between roots, fill it up over the roots. The roots will actually help to displace the water when filling up the water, creating less turbulation.
1. Sort of. They can be setup to be okay, though still not ideal. Plants use ammonia, but other wastes will build up, requiring frequent water changes.
2. Yep, though still maybe on the cool side. Bettas prefer upper 70's--much warmer than I'd like my house. In cooler water, bettas are prone to fin rot and bacterial infections.
3. Not a big deal, though adding the filtration is a good plan. There must be a large area of open water that the betta can get to easily. Bettas and other labyrinth fish can actually suffocate if access to the surface is limited--oxygen levels in the water aren't sufficient. They must get to the surface to breath.
4. More than weekly. Bettas are carnivores, but I still prefer to feed them daily to every other day--weekly just wouldn't cut it.
5. The plant can simply be set aside during water changes--the most commonly used plants are sturdy enough to be fine laying on their side for a few minutes. This is preferably to leaving the plant in place, since that will limit your ability to clean the substrate of waste and uneaten food.
FWIW, I think these can be a nice setup, but more maintenance than I will deliberately give myself for one fish. A 5 or 10 gallon tank will be cheaper in the long run, simply because it will take less work to keep stable.