Cantonese slang, meaning "see the light of death". It is used as a metaphor for the death of a fish that dies when it is brought to the surface of the water.
In Hong Kong, "white rice fish" is a common name for cheap canvas shoes, usually from mainland China. These shoes have a white canvas body and a thin rubber sole (usually green or black), hence the name "white rice fish". The "White Rice Fish" is usually sold at a price of just over HK$10, making it a popular sports shoe for primary and secondary school students attending physical education classes. In addition, "White Rice Fish" is also a popular casual shoe for the lower class, morning walkers and renovation workers. Another common occasion for the use of "white rice fish" is Chinese funeral ceremonies. In a Chinese funeral, the entire body of the attendee must be white. Some people do not have white shoes (white shoes get dirty easily), so they buy cheap "white rice fish" for the funeral.