Platypuses eat mostly worms and other small creature in the water. They have no teeth but they have grinding pads in their mouthes. They eat in the morning, and once again in the evening. They also eat frogs, shrimp, larvae, fish, and tadpoles.
Courtesy of skywalker.cochise.edu/wellerr/students/platypus1/duckbill.htm
Some of the platypuses predators include snakes, water rats, goannas, spotted quolls, eels, hawks, owls, eagles, and feral cats. Some of the northern platypuses are in danger of crocodiles and dingoes.