Pleuronectidae and they sink to the bottom. They are found on the bottoms of oceans around the world, with some species, such as the Atlantic halibut, "Hippoglossus hippoglossus", being found down to . The smaller species eat sea-floor invertebrates such as polychaetes and crustaceans, but the larger righteye flounders, such as "H. hippoglossus", which grows up to in length, feed on other fishes and cephalopods, as well. They include many important commercially fished species, including not only the various fish called flounders, but also the European plaice, the halibuts, the lemon sole, the common dab, the Pacific Dover sole, and the
Peters' elephantnose fish fish can use its electosensing to detect moving prey and worms in the substrate. Although the elephant nose fish was once thought to have poor eyesight, it is now known to have good low light vision. Its eyes use a combination of photonic crystals, parabolic mirrors and a clustered arrangement of rods and cones. Peters' elephantnose fish Peters' elephant-nose fish ("Gnathonemus petersii") is an African freshwater elephantfish in the genus "Gnathonemus". Other names in English include elephantnose fish, long-nosed elephant fish, and Ubangi mormyrid, after the Ubangi River. As the Latin name "petersii" confirms it is named after someone called