The Hagen cubes are much too small- I recommend a 5 gallon, or 2.5 at least.
Bettas, i find, are happier without lights, so I wouldn't bother getting one.
I get my tanks from petsmart and PJ's Pets, if there is one near you.
Some people use filters, some don't. (I don't.) However, if you don't get a filter, you will have to do more frequesnt water changes (although you do small water changes now and them anyway.) If you do decide to get a filter, make sure it is a very weak onel because bettas are really not stonf swimmers at all.
Any regular, good heater will do, and you'll need a thermometer to monitor the temperature. Also, get a lid for the aquarium- your cats might decide your fish looks yummy and they also jump!
Lastly, get a hiding place or two for your betta, and some silk or live plants if you want (or plastic, as long as they cant rip your bettas fins.)
Last edited by Betta Slave; 04-23-2010 at 12:32 AM.