The male bonds with only one female for life if one dies or they removed for each other they will live the rest of their lives alone. They are from the Congos and they love high current and they swim across the bottom and they rest one the bottom due to their underdeveloped bladders. Mine are so funny I love to watch them. They get up to six inches and are non-agressive. My Frontosa seem to love them and no one harms anyone in my tank. They lay eggs and I have Lots of babies and they all swim out in the open it is funny not even my 6 inch Catfish will eat the babies.