What does "watching goldfish" mean? And "goldfish"?

/kloc-In Sham Shui Po in the 1960s, a public housing village was established in densely populated Hong Kong. At that time, light industry rose in Hong Kong (mainly textiles, clothing, toy processing, etc.). ), and a large number of women are employed, and their children lack parental care. During this period, many vicious cases of underage girls being molested and raped occurred one after another. According to the investigation, a man lured a little girl to be molested or raped in a deserted place on the grounds of keeping goldfish on the rooftop and taking her to see it. And his most common sentence is: "Little sister, will uncle take you to see the goldfish?" The goldfish eyes are big and cute ... "At that time, some people in the society called it the case of the goldfish guy ('guy' is a name for adult men in Cantonese, which is not very respectful, but generally does not contain derogatory meanings). The police quickly arrested Fang, a 29-year-old plastic factory worker. Later, he confessed to the crime of 18 and was sentenced to life imprisonment, which was the heaviest punishment since the indecent assault case at that time. Since then, the word "goldfish guy" has spread like wildfire, and it has become synonymous with a sex maniac who specializes in abducting and selling children for indecent assault. Now saying "Uncle shows you the goldfish" in Cantonese is a somewhat obscure "colored" joke. Goldfish has become another name for strange uncle (strange millet, implying pedophilia).