Ya, I'd say you'd need a 5 gallon tank or more for and ADF and a betta. My ADF lives in a 5 gallon with a DP. My bettas have always gotten along great with frogs. It can be kind of tough to get food down to the frogs sometimes, when the bettas snatch up anything they see. ADFs make great pets though. My frog, Darwin, has learned to recognize me and always comes to the glass when he sees me sitting near the tank. He's also learned to follow my finger along the glass to be led to food, which he doesn't always notice right away - ADFs have poor eyesight. I would definatly reccomend them if you ever upgrade to a larger tank.