"I moved my betta from a tiny tank, one of those horrible 1/2 gallon ones that are actually made so that you can fit two uncomfortably, into one of these. Betta tanks shouldn't normally have filters because filters are noisy and cause vibrations in the water- bettas need calm water. I love this tank and use it w/o the filter. It's easy to clean and the light is good to keep the tank a bit warmer if you don't have a betta tank heater. (75-85 F is good) I got a thermom. that sticks right to the side of the tank. I only left a plant and a layer of stones on the bottom and my betta loves it. There's plenty of room."