Small mud carps or “Trey Riel” (Henicorhynchus entmema and H. siamensis) are the most commercially important keystone species in Cambodia, according to Wonders of the Mekong project. These two species are also very important to the ecology of the Mekong River basin and the food security of people living in the region..

In Cambodia’sTonle Sap Lake, anyone with the permission of the government can catch Riel for only five to six days from the 8th day of the dark moon to before the full moon, based on the Khmer calendar. After dressing the Riel, Khmer women put the fish in bamboo containers and crush it with their feet, similar to wine made by stepping on grapes.

Cambodian riel (Money). Popular belief suggests that the name of the currency comes from the Mekong river fish, the riel (“small fish” in Khmer). It is more likely that the name derives…