When breeding Bettas many use a system called Betta baracks where lots of mini tanks are linked together saving time with water changes. The diagram below shows a main tank which has been split so that the right hand side acts as the filter. Each compartment is filled with different media. Water returns back to the tank from the barracks and drops into the filter compartments where it is filtered before being pumped up the pvc pipework. Each betta tank is plastic and has a hole drilled an inch from the top. The tanks are drip fed so that water is constantly flowing through them. When the water reaches the hole in the mini tanks it overflows into the guttering that they are sat on and the water then flows through the gutteringand supplies the tanks below. This system has advantages, just 1 water change, a massive filter, only one heater. The main disadvantage is that diseases can be pumped round and affect all of the other males.