Atlantic halibut Atlantic halibut The Atlantic halibut ("Hippoglossus hippoglossus") is a flatfish of the family Pleuronectidae. They are demersal fish living on or near sand, gravel or clay bottoms at depths of between . The halibut is among the largest teleost (bony) fish in the world, and is an endangered species due to a slow rate of growth and previous overfishing. Halibut are strong swimmers and are able to migrate long distances. Halibut size is not age-specific, but rather tends to follow a cycle related to halibut (and therefore food) abundance. The native habitat of the Atlantic halibut is the temperate and
Flat pebblesnail Flat pebblesnail The flat pebblesnail ("Lepyrium showalteri") is a species of freshwater snail, an aquatic gastropod mollusk in the family Lithoglyphidae. This species is endemic to the United States. This snail has been listed as endangered on the United States Fish and Wildlife Service list of endangered species since October 28, 1998. "Lepyrium showalteri" is the only species in the genus Lepyrium. "Lepyrium showalteri" is the type species of the genus "Lepyrium". Lepyriidae is a synonym of Lithoglyphinae. The flat pebblesnail is a small snail in the family Lithoglyphidae; however, the species has a large and distinctive-looking shell. This snail's