Palaemonidae is a family of shrimp in the order Decapoda. Two subfamilies are distinguished: Palaemoninae and Pontoniinae. Palaemoninae are mainly carnivores that eat small invertebrates and can be found in any aquatic habitat except the deep sea. The most significant genus is Macrobrachium, which contains commercially fished species. Pontoniinae inhabit coral reefs, where they associate with certain invertebrates such as sponges, cnidarians, mollusks and echinoderms as cleaner shrimps, parasites, or commensals. They generally feed on detritus, though some are carnivores and hunt tiny animals.