Keeping your young fry and cherry shrimp out of your aquarium filters can be a challenge. most filters are not designed well enough to keep the smallest inhabitants out. Sponge filters are a cost effective as well as an efficient way to protect your small fry or baby shrimp. The home made filters and are made with common easy to find parts. The best part they very cheap to build and cover all aspects of the filtration process. They are powered buy simple air pump and are very low maintenance.