Wow, I'm surprised at the amount of people here who actually don't use or haven't used them in the past and had fish that lived for a long time.
Like I said, I still definitely intend to get one for each fish. I'm thinking about spoiling myself (and my fish, haha!) this Christmas and invested in a 5 or 10 gallon filtered tank with a light and separating screen so I can just put both of them in it. And get a heater for the tank, of course. That way, I won't have to change 2 separate tanks and I can have a filter which will help keep the water clearer and cleaner. Plus, they'd have more room and I could get some really nifty tank decor.
Totally off-topic, but I got one of those betta leaf hammocks for my betta in my 2.5 gallon, just to see if it's a gimmick or not. I put it near the surface, and OMG! He really uses it! It's SO CUTE! I am definitely gonna get another one for my other betta next time I go to Petsmart. It's a cool idea. Kudos to the person who invented it.
Thanks to all of your for responding! I'll get that heater by the end of the year. They may not be at their best, but at least they both seem pretty happy. I know they would be best with it. I just wish I wasn't so poor. A looked at prices and they are pretty expensive. Plus, I am gonna research some of the ones recommended. I'd like to get a small one for my little tank, as recommended. Or I should just probably wait until I get a bigger tank next month.
I wish I never 'discovered' these things (or more like took one home impulsively)! They are pretty addicting. If I had things my way, I'd have a fish room like some hardcore fish people have. But I'd only be able to do that if I didn't work full time and I was pretty well off monetarily.
Heck, people always tell me I'd have my own zoo if I could. I love pets. :P