Small and medium-sized filters such as waterfall filter, water goblin and external micro filter cartridge are suitable for guppy. Because guppies are not very big and their metabolism is not high, the pollution to water quality is not serious. In addition, when they live in the wild, they all live in gentle water flow, and when they are raised in captivity, they can't use large water flow, so they can't use large filters. Most breeders will choose water goblins, because they are small in size, strong in filtering ability and moderate in water flow, which will not affect the normal life of guppies. Furthermore, water goblins can also provide a living place for nitrifying bacteria, which makes the water quality of guppy more stable.

Whether the guppy filter needs to be opened normally is best determined according to the feeding density. If it is a normal feeding density, the breeder does not need to open the filter normally, but can only open it during the day and close it at night. If the water body is large, the breeder can ensure the normal frequency of water change, and it is ok not to open the filter.

If the feeding density is too high, it is necessary to open the filter normally. Because of the high density of water pollution is more serious, normally open filter can slow down the deterioration of water quality. Although always opening the filter can keep the water clean, breeders also need to change the water regularly to avoid bacteria breeding in the water.