Gold fish were popularized by emperors of the Tang dynasty (618-907 AD) who selectively bred the golden carp in royal ponds. Apparently their colour was caused by genetic mutation. Since then, carp have had a large presence in Chinese culture.
Linguistically, all fish are considered lucky, as the word for fish, “yu” is pronounced the same as the word for bounty or surplus. The fish are also mainstays in Chinese art. Interestingly enough, feng shui dictates that having a painting of a fold fish is just as lucky as having an actual fish. No wonder you can buy paintings of fish everywhere!
Numbers are hugely symbolic too, based on their sounds in multitonal Cantonese. The number eight, “baat”, sounds similar to the word for prosperity “fat dat”, and to have it in your telephone number or your license plate is indeed fortunate. The number three, “saam” sounds like the word for lively of flourishing, “saan”, so that’s another lucky number.
However four, “say”, sounds similar to death “say” (in a different tone) so it is the number to be most avoided. Many flats and office buildings in Hong Kong and China do not have a fourth floor. Sometimes even the fourteenth, twenty-fourth etc. floors are omitted too. Number 13, which is believed to be an unlucky number in Western cultures, does not matter in Hong Kong. It appears everywhere.
Not surprisingly, Western people tend to get phone numbers that include the number 4 in Hong Kong – I happen to have two 4s in my mobile phone number and I guess Smartone tried to make up for it, by giving me a number 8 too. I guess two 4s and one 8 still mean bad luck but not as bad :)