Oh also - Water Hyacinth! It's a huge plant with a long root system, it's actually a pond plant I think and can't be kept outside in the winter if the winter is cold because it'll get frostbite.
I prefer water lettuce than water hyacinth. Their roots don't need substrates and they work the same way. But IMO WL leaves provide better nesting places.
I use anacharis, mostly anchored (5 each) then bunched to provide hideouts for the female. In addition I also add bacopa and cabomba (also anchored) plus other grass like plants in small pots.
Check out the eBook Betta Fish Care Made Easy
