Do rich children have to give zakat?
Zakat is a worship. Zakat is not fard on children just as other worships like prayer (salat), fasting (sawm) and pilgrimage (hajj).
According to Shafi’i madhab, zakat is taken from the wealth belonging children and mentally disordered people, too. Because, zakat is a duty about wealth. If the owner of wealth is Muslim, zakat is taken although he/she is a child or mentally disordered.