Chirostoma
Chirostoma is a genus of Neotropical silversides from the Lerma River basin in Mexico, including lakes Chapala and Pátzcuaro. Fish in the genus collectively go by the common name charal/charales in their native range (a name also used for the related "Poblana"). They are heavily fished, but several of the species have become threatened due to habitat loss (pollution, water extraction and drought), introduced species and overfishing. Three species are considered extinct: "C. bartoni" (disappeared 2006), "C. charari" (1957) and "C. compressum" (1900). Four others have not been recorded recently and may also be extinct. Appearance and behavior . "Chirostoma" are generally silvery-white, pale gray-brown or dull yellowish in color, and have a long horizontal line on the side of the body (inconspicuous and more spotty in some species). They vary in size, ranging from species that are less than long to species that can surpass . Despite the differences, there is great overlap in the food choice of these filter feeders with the main diet being composed of various small organisms (mostly planktonic) such as copepods, cladocerans, rotifers, amphipods, oligochaetes, nematodes, insect larvae, and fish eggs and embryos (including those of silversides). They are ovoviviparous and employ  external fertilization. During spawning each female lays a few hundred to a few thousand eggs. Species. There are currently 23 recognized species in this genus. Additionally, the 4 "Poblana" species are sometimes included in "Chirostoma" instead of being placed in a separate genus. Several species of "Chirostoma" can hybridize. Culinary use. Dried "Chirostoma" can be fried with salt and lemon and covered with fried egg with garlic or chili. They can be added to omelettes or fried pancakes in green sauce. Availability. "Chirostoma" can be purchased at restaurants on the shores of Lake Chapala in local markets. They are typically  sold dried and are affordable. "C. estor" is aquacultured, and "C. humboldtianum", another potential candidate for aquaculture, has been bred in captivity.