You may happen to see fish-shaped streamers in Japan at this time of year.
The streamers are called "Koinobori" showing carps ascending against a stream, and they are put up wishing for young boys' happiness and future success, whereas Hina Dolls are set out to pray for girls’ happiness.
The Boys' Festival is May 5th, but this day is actually called Children’s Day, and considered to pray for both boys' and girls' good health and happiness.
In Otaru, a lot of Koinobori are put up over the River Katsunai every year, and they attract people’s attention as a charming sights of spring.