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
Jellynose fish Jellynose fish The jellynose fishes or tadpole fishes are the small order Ateleopodiformes. This group of ray-finned fish is monotypic, containing a single family Ateleopodidae. It has about a dozen species in four genera, but these enigmatic fishes are in need of taxonomic revision. The scientific name means ""Ateleopus"-shaped", from "Ateleopus" (the type genus) + the standard fish order suffix "-formes". It ultimately derives from Ancient Greek "atelís" (ἆτελής, "imperfect") + "pús" (πούς, "foot") + Latin "forma" ("external form"), the Greek part in reference to the reduced pectoral and ventral fins of the jellynoses. Jellynoses are deep-water, bottom-dwelling, marine fishes.