Most species are bottom dwelling and many live in tubes or cases in the substrate. They tend to be herbivore-detritivores in their feeding habits. Adult midges are generally short-lived and do not feed. Isopoda Aquatic Sow bugs Aquatic sow bugs, which inhabit a wide variety of shallow freshwater environments, are usually found under rocks or amid vegetation and debris. Most are omnivore-detritivores with a life span of about a year or less.
Most scuds avoid light and during the daytime are found among vegetation or under rocks or debris.
They are omnivorous, general scavengers in their feeding habits. Scuds typically need abundant dissolved oxygen and are therefore more sensitive to organic pollution than aquatic sow bugs. The phylum Platyhelminthes includes the flattened, unsegmented worms, many of which are parasitic or marine. Most of the free-living freshwater forms are planarians that are usually found in the substrate of shallow waters, often under rocks and detritus to avoid light. Most are carnivores and scavengers.