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 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 "Peters" (probably Wilhelm Peters), although the apostrophe is often misplaced and the common name given as "Peter's elephantnose fish". It uses electrolocation to find prey, and has the largest brain-to-body oxygen use ratio of all known vertebrates (around 0.6). Peters' elephantnose fish are native to the rivers of West and Central Africa, in particular