As there is no such thing as a purple platypus, this question is impossible to answer.
Platypuses eat crustaceans and larvae that live on the bottom of creek and river beds.
There is no such thing as a purple platypus,
Platypuses are not purple. The colour of a platypus's fur is dark brown over most of its body, with a grey undercoat. Its belly is gold-coloured or silky grey.
No. Platypuses do not eat mangroves or any other plant matter.
Platypuses do not eat earthworms or other terrestrial worms. They eat aquatic annelid worms.
No. Platypuses eat small water animals such as aquatic insect larvae, fresh water shrimp, annelid worms, yabbies and crayfish. They do not eat anything terrestrial.
No. Cougars do not eat platypuses, for the simple reason that platypuses and cougars occupy different continents. Platypuses are endemic to Australia, and there are no cougars in Australia.
No whales eat fish
Probably the largest thing which platypuses eat are small yabbies, which are a type of freshwater crayfish.
Platypuses do not eat plankton, so they do not need to find it.
Platypuses do not eat land food. They feed entirely off crustaceans and small water creatures.
No. Platypuses do not eat grass or any other vegetation. They are carnivorous, feeding only on small aquatic invertebrates.
Platypuses do not have teeth, but hard bony plates which they use to grind the food.