betta because it would be one fish and have great personality bettas are everything exept sensible to water parameters i literaly have a betta in a pond that is the most beatiful betta i have is in a back yard pond in murky water and he is perfect !!! bettas where my fist fish and i didnt now anithing about fish keeping i thougth they could go in bowls but he was my introduction to fish keeping rest in peace 😌