1boy, 1girl, aged up, book, brother and sister, cigarette, collared shirt, fins, fish tail, furry, furry male, greyscale, grin, hair between eyes, hand in pocket, holding, holding book, miniskirt, monochrome, muscular, muscular male, pleated skirt, pointing, pointing at another, ponytail, school uniform, shark boy, shark girl, shark tail, sharp teeth, shirt, short sleeves, siblings, skirt, smile, smoking, tail, teeth