Sponge filtration is an often overlooked type of filtration for freshwater and even marine aquariums. Many persons look past their simplicity as ineffective, but therein lies their quality. I have used them for my aquarium maintenance for 27 plus years with excellent results. Here then is a list of their attributes:

[1] Simple to use, most run on very basic air pumps or power heads.

[2] Excellent biological filtration, they are very porous and can maintain very large bacterial colonies in proportion to the space they occupy.

[3] Mechanical filtration, although they are not the best mechanical filters, they still do a good job for their small size and make excellent supplementary filters.

[4] Very few dead areas trapping pockets of noxious bacteria, unlike under gravel filters and even wet/dry filters (which in my experience are over rated).

[5] Simple to clean, simply remove the sponge and squeeze or rinse in old aquarium water or dechlorinated tap water.

[6] Excellent compliment to live rock filtered reef aquariums.

[7] Probably the best choice of filtration for breeding tanks, hospital tanks, and even discus aquariums, due to the fact that they do not suck in baby or weak fish or attract noxious bacteria.

[8] For cichlid breeding they excel, as they are not easily disturbed by cichlids tendency to dig.

[9] Inexpensive

[10] Now available in larger sizes for aquariums over 60 gallons.

[11] There also are sponge filters that are used as a "pre-filter" for intakes of canister, wet/dry, power filters and more. They offer increased bio-filtration to your existing system, as well as protection from baby fish, plants, or anemones from being sucked into the intake of your existing filter.