Hey, you have some pretty betta's! I was reading in the thread and I believe you are doing all you can! And its great seeing someone who cares so much for their fish! If you can afford it though I agree that a heater would be a great thing! They are only $15 at walmart and heat your size tank perfectly! Heat will just help ward of illness that fluctuating temps can cause. Anyways welcome to the forum and look forward to seeing more of you around!