If you're looking to add a wave maker to your freshwater aquarium, there are a few things you'll need to consider before making your purchase. First, you'll need to determine the size of your aquarium. A small wave maker may be sufficient for a nano tank, but a larger one will be necessary for a standard size aquarium. Second, you'll need to decide how much water movement you want in your tank. A gentle flow is suitable for most fish, but some species require more vigorous water movement. Finally, you'll need to take into account the power consumption of the wave maker. A higher wattage means more power consumption and a higher price tag. With these factors in mind, you should be able to select the right wave maker for your freshwater aquarium.