金鱼藻（学名：Ceratophyllum demersum）是金鱼藻科金鱼藻属的植物。为鱼类的饵料，也可作为猪的饲料。

多年生草本的沉水性水生植物。茎细长分枝；叶子轮生，一再分裂成线状；秋季开小花，雌雄同株；果实为瘦果。

Ceratophyllum demersum, commonly known as hornwort, rigid hornwort, coontail, or coon's tail, is a species of Ceratophyllum. It is a submerged, free-floating aquatic plant, with a cosmopolitan distribution, native to all continents except Antarctica. It is a harmful introduced weed in New Zealand. It is also a popular aquarium plant.