Detritivores are organisms that consume non-living organic matter, such as dead plants and animals. Earthworms break down dead organic material in the soil. Millipedes feed on decaying plant matter. Woodlice, also known as roly-polies, consume decaying wood and leaf litter. Jellyfish are carnivores that feed on plankton and small fish, while seahorses are also carnivores, preying on small crustaceans and fish.