These stickers are for “kodomo no hi” or children’s festival. is a Japanese national holiday which takes place annually on May 5, the fifth day of the fifth month, and is part of Golden Week. http://www.ebay.com/itm/Japanese-Stickers-Childrens-Day-Festival-Kodomo-no-hi-S63-/140978884892
It is a day set aside to respect children’s personalities and to celebrate their happiness. It was designated a national holiday by the Japanese government in 1948.
There are many “koinobori” carp shaped flags. The black carp at the top represents the father, the red carp represents the mother, and the last carp represents the child, with an additional carp added for each subsequent child with color and position denoting their relative age.