The water louse is a native freshwater crustacean. They are found in most freshwater enviroments in the UK including  rivers, lakes, streams, ponds and ditches. They are detritus feeders that eat dead plants, dead insects and other organic matter they can also be fed fishfood, algae wafers or sinking pellets. They can be kept in both coldwater and tropical aquariums as well as ponds and would make an excellent addition to a wildlife pond. They will live in the sponges of pond filters where they will eat sludge and waste , They are  a great natural food source for fish and a good source of calcium for amphibians.