Wikipedia
Prahok (ប្រហុក) is a crushed, salted and fermented fish paste (usually of mudfish) that is used in Cambodian cuisine as a seasoning or a condiment. It originated as a way of preserving fish during the longer months when fresh fish was not available in abundant supply. Because of its saltiness and strong flavor, it was used as an addition to many meals in Cambodian cuisine, such as soups and sauces. A Cambodian saying goes, "No prahok, no salt", referring to a dish that is of poor flavor or bland thus highlighting its essentiality in Cambodian cuisine. Prahok has a strong and distinct smell, earning the nickname "Cambodian cheese" among food writers. Prahok is usually eaten as a main course with white rice and vegetable such as yardlong bean, cucumbers, and Thai eggplant.
Because it is easily stored and preserved, Prahok is sometimes distributed as a donation to victims of flood or drought by charities and other organizations. It can be eaten cooked or fried, but is usually not eaten raw because of health issues (raw Prahok cannot be stored long due to spoilage if not consumed in a short period) and the unpleasant smell it makes.