The types of fish that penguins eat include sardines, smelt, herring and anchovies. Fish make up different portions of the diets of different species of penguins. For instance, fish make up four percent of the diet of chinstrap penguins and 90 percent of the diet of emperor penguins.
In addition to eating fish, penguins also eat krill, squid, crustaceans and amphipods. Krill are shrimp-like creatures that are approximately two inches in length. They are typically eaten by macaroni, Adélie and chinstrap penguins. Juvenile squid and other small squid such as arrow and greater hooked squid become part of the diet of penguins during the summer months when they are plentiful. They are typically eaten by gentoo, emperor and rockhopper penguins.
Penguins also dive down to depths as great as 330 feet to retrieve crustaceans such as shrimp, crab and sand hoppers from the ocean floor. Amphipods, which are found underneath sea ice, are an important part of the diet of chinstrap penguins, as well as fish, seals and other types of birds. Amphipods resemble shrimp, although they do not have a hard outer covering over their thorax like many other crustaceans.
There are 17 species of penguins that survive on a variety of seafood throughout the ocean. Their diets are typically determined by the types of seafood that are available during each season.