The Goldfish Seller, by Wada Sanzo, 1939. A sign of early summer during the 19th to the 20th centuries. Itinerant salesmen would wander the streets of Edo/Tokyo with glass fish bowls, water, fish, and a distinctive high pitched call. They had mostly disappeared before 1980. 
Traditionally a job for younger men, carrying around 40kg of materials on carrying poles for kilometers in the summer heat could not have been easy. It wasn't a year round job, only for a couple of months to make some extra money.
Before plastic bags, buyers would take their goldfish home in simple round glass bowls (called kingyodama) tied with string. They could be hung on the veranda before being transferred to larger clay or ceramic pots usually in the garden or in front of the house facing the street.
Before glass aquariums were invented, the traditional way to view goldfish was from above (上見, uwami), so fish was bred to look their best from above and not from the side like modern breeds today (which explains many of the stranger looking old fashioned breeds).
When the traditional room heaters of Japan (the hibachi), were phased out in the 20th c., many of them found a second life in front of shops and in gardens, as gold fish ponds. Very decorative and a clever reuse.
Today you can't walk far in a Japanese town without seeing these in the streets in front of homes and stores. It is a great way to catch the attention of potential customers (especially children love them), and they are an example of one of the Japanese patterns of #GoodUrbanism.
