I am planning to have a 11 gallon tank (18 x 12 x 12) with just 1 male Betta. Now since Bettas don't like filter, I plan to have around 8 plants so that the plants can act as a filter. But the issue is Betta tanks should ideally not have light, so my tank would be without light. The tank would get about 2 hours of sunlight. I don't plan to add CO2. Which are the fast growing plants which can grow without much light and additional CO2 ?