Yu daan (fish balls) are probably Hong Kong's most popular roadside snack. A chuen (skewer) of boiled yu daan, dunked in a yellowish, curry-like gravy and served with a helping of chue cheong fun (pig-gut noodles) is one of the first items expatriate Hong Kong Chinese seek out when they return, and branches of popular yu daan outlets have opened in emigrant destinations from Sydney to Vancouver.
Like many local seafood offerings, yu daan are originally a Chiu Chow dish. Chiu Chow (or Chaozhou), a region in northeast Guangdong province, was noted for centuries for its poverty, which impelled generations of migrants to seek a better life overseas. Little that was edible was wasted in such lean times. Fish too small or bony to be eaten whole were meticulously scraped of their flesh. The resultant pulp was mixed with rice flour, yam starch and other extenders then formed into balls.
Freshwater fish were commonly raised in ponds in the northern New Territories,
in particular around Mai Po, Lok Ma Chau and San Tin. Popular species included grasshopper fish and a variety of catfish. Boney and rather bland, pond-bred fish
are ideal for the snacks. Cheaper yu daan are made from shark meat and other inexpensive fish.
As they are labour intensive to produce, fish balls were often made in areas where sun yee mun (new immigrant) and other low-cost labour pools were available. For decades, large quantities of Hong Kong's fish balls were manufactured in the squalid environs of Kowloon Walled City - a Chiu Chow stronghold. Hygiene standards were virtually non-existent, triad protection meant sanitary inspectors never dared call and - in true Hong Kong fashion - everyone raved about the taste.
Yu daan dong (fish-ball stalls) acquired an unsavoury secondary reputation. In Cantonese slang, fish-ball stalls euphemistically referred to a specific type of brothel. Yu daan dong were common features in areas close to typhoon shelters, such as Yau Ma Tei, Causeway Bay and Aberdeen, and were staffed mostly by impoverished haam shui mui ('salt water girls', or Tanka boat-girls).
Darkened recesses accommodated yu daan mui (fish-ball girls), who performed various services. Apparently the motions employed were meant to imply the rolling and kneading by hand of fish paste into balls. Many such stalls also - quite legitimately - sold steaming bowls of yu daan fun (fish-ball noodles) as a front for their more profitable activities. A few still survive, though the backrooms of many karaoke parlours are really yu daan dong by another name.