I got my betta 3 months ago, he was living in a 1/2 hallow tank. He seemed happy up until a week ago when he stopped eating and began laying on the bottom and only coming up for air. How can I help my betta who is laying at the bottom of his tank? up vote 6 down vote favorite. If your betta is lying at the bottom of the tank, are his fins clamped? Betta Laying on Tank Bottom | Betta Fish Care for Fighting Fish Enthusiasts.