Hey Jess, the males are in a arge custom built tank. its pretty much a square theres a long bay at the back (nero lives in here and it will be divided to share to Charz) then in front is two rows across divided into 4 so theres 8 bays, its all glass with 5mm at the bottom of each divider to allow water flow, using a larger gravel prevents fish getting sucked under dividers, i cover the bays with plastic egg crate to stop bay jumpers lol