The pomacea canaliculata (or cana for short) are another variety of apple snail. Canas get to be softball sized and devour plants. They'll tear up your tank in no time flat.
Apple snails are often called mystery snails. When you go to the LFS, the little sign will say "Mystery Snail" and then either pomacea bridgesii or pomacea canaliculata. Just make sure the one you're getting says bridgesii (or however it's spelled, can't remember right now -- brigs for short).
They like higher pH levels. Love eating soft veggies. Nuked or blanched broccoli, zucchini, yellow squash, any veggies with a high calcuim content. I also put in calcuim tablets or weekend feeders for mine to eat. Others add liquid calcium to the tank periodically to help with shell growth.
Snails are really quite fun!
Just be warned, sometimes bettas don't like anyone in their space. I had my snail in my 5 gal. with my male betta, and the betta harassed the snail to the point that I had to move the snail. Kept the snail pinned in the corner of the tank. And sometimes bettas don't take notice of the snail at all. Just depends on their personality.
Keep us posted! I love to hear snail stories.