I have 3 peas in a 20g planted breeder, with otos, hillstream loaches and snails. I call them the 3 amigos, the 3 stooges or murder beans, depending on the day. They can usually be found together, hunting snails and morsels of whatever they think looks edible. No fighting so far but I do have lots of line of sight breaks and hidey holes just in case things get rowdy.