Penguin diet can be classified in five groups of penguins.
The diet of the King penguins rely mainly in fish and squid and include a small amount of krill and other crustaceans. Fish constitute 80-100% of the diet, except in winter, when fish is only 30% of the intake. Lantern Fish are the main fish eaten by Penguins. The Emperor penguin diet is made up fish, crustaceans and cephalopods.
This group includes the Adelie Penguin, the Chinstrap Penguin and the Gentoo Penguin. Their diet is mainly composed by Antarctic Krill, siverfish and glacial squid. The amount of fish in their diets varies from place to place according with opportunity going from 15% in places with less fish up to 50% in places with abundant fish.
The little penguins group is made up by the little blue penguin and the northern little penguin. This group mainly feed on fish, squid and other small sea animals, the main difference with other groups is that they are shallow hunters not going deeper than 2 m.
In this classification you can find the Magellanic Penguin, the Humboldt Penguin, the Galapagos Penguin and the African Penguin. The mostly feed on small fish like sardines, cephalopodus like cuttlefish and squid and some other small crustaceans. African Penguins in particular add anchovies and pilchards to the previous diet.
In this classification you can find only theYellow-eyed Penguin. The feed up to 90% on small fish and cephalopodus like the arrow squid.
This large group is conformed by the Fiordland Penguin, the Snares Penguin, the Erect-crested Penguin, the Southern Rockhopper Penguin, the Northern Rockhopper Penguin, the Royal Penguin, the Macaroni Penguin and finally the Chatham Islands Penguin. The feed on krill and other small prey like small fish, squid, octopus and crustaceans.