If you are going to continue with your Betta in the tank it`s in now, the minimum you need to be looking at is at least 50% water change every other day. You can buy cheaper makes of conditioner, most of them tend to do the same job, just adjust the dose accordingly to the amount of water. Your Betta WILL NOT go into shock, make sure the temperature you change is approx the same as the temperature you`re removing.
You do NEED to get a heater, but a filter in that size tank is going to take up too much room, your Betta wouldn`t really have any room to move.
I`m sure you`ll work it out, read through the replies you`ve had and go with what`s best for your Betta if you intend to keep him.
It`s not always easy to be able to go out and spend money but the minimum you need has already been explained here and it won`t cost you a lot to give your Betta a decent, clean, happy home.
Last edited by Elisew; 05-01-2009 at 01:00 PM.
Reason: add info