Not many nations are crazy for fish heads like Singapore -Fish head curry, fish head steamboat and then there's fish head beehoon. Fish head beehoon, I was told, is uniquely Singaporean dish which is Cantonese but not sold in mainland China. The chopped up fish heads are fried in oil until crisp and aromatic then simmered together with sweet fish & chicken based stock. The garnish depends from stall to stall but is not elaborate as -say beef noodles. Some stalls I recall serve with only greens with a dash of deep fried shallots. It is simple and bold dish. Some add XO Brandy to the soup for complexity. But this could be a marketing tool. I am extremely skeptical whether they use the REAL XO Brandy (meaning Extra Old) which is cognac aged in cask for at least 6 years. Some add milk to the soup and some don't. It is often said that adding milk is cheating (in order to achieve the milky colour) but flavor of the soup gets an extra kick and sweetness so I don't really find it cheating. But the science behind milky colour is just like Japanese tonkotsu (pork soup) ramen. You need some fat, liquid and an emulsifier. In this case, the fat is the deep fried bones, the liquid -the stock, and the emulsifier is the collagen from the bones that's melted away by boiling for quite some time. The oil and liquid usually don't mix with one another but with the addition of emulsifier agent, they will be mixed definitely or indefinitely depending on what it is. Good example is mayonnaise (and hence the solid color achieved by mixing vinegar and oil with the help of egg yolk). The noodle for fish head beehoon is not the thin type of beehoon but a thicker one known as chor beehoon like the one used for laksa. I haven't come across a stall that sells this with other type of noodles (then it won't be fish head beehoon but fish head noodle). But is chor beehoon the very best match with the soup? Some say that the reason why they do not use the thin type of beehoon is that they suck up the soup. Then why not use mee sua? Ah, my friend told me this is also not a good idea :-)
Lot of stalls use the fresh water fish such as Toman fish -game fish and a lot of them are farm raised in Malaysia. I found a shop at Chinatown complex that specializes in toman fish. They were quite huge -around 70cm. They also look kind of vicious.