This is a simple but strong Shorts idea. The “fish in street gutters” hook feels unusual and instantly scroll-stopping, especially for Japan/travel content. Keep it calm, visual, and almost documentary-style with natural street sounds. Add tags like: Japan travel, Tsuwano, hidden Japan, unusual places, travel shorts, fish gutters, Japan town.

Cute, evergreen idea, but I don't think your hook is there yet. If you're only relying on B-roll and music, once people get bored, they will scroll away. Maybe a storytelling element would help or something to retain viewers?

Show the street and water channel together before going tight on the fish. Without that wide shot, a viewer may not realise where they are. I'd also move “Tsuwano, Japan” from the final frame to the opening shot and let the natural sound do the rest.