The odour comes from a red washing-up bowl filled with grey sludge in which float pieces of silver fish. The smell is outdone only by an equally pungent pile of grey paste with bits of rotting fish poking out. The wet grey stuff is fish sauce, while the other is fish paste, although both seem to be called prahoc; they smell and look awful to the unaccustomed nose and eye.
Prahoc is a vital flavouring in almost everything savoury in Cambodia. So common is it that the national flag, which features the ubiquitous emblem of Angkor Wat, should be soaked in the stuff.
They’re both different grades of prahok. It describes a whole genre of fermented freshwater things. Journalist and blogger Ed Charles takes on fish in Cambodia and takes off with one of my jokes about prahok in The Australian newspaper. It’s a joy to read an article where a journalist doesn’t just eat fish amok.
There’s also a bit of a mix up between tuk trei (fish sauce, made with saltwater fish) and trei riel (“riel” fish – a few different varieties of small fish used to home-brew prahok) further down in the article, but it is understandable since there are no written resources where you could fact check such details.
See: The Australian’s A fishy pleasure