Blue-green and red algae, diatoms, larval and adult forms of small insects, crustaceans, molluscs, and small fishes make up the main diet of flamingos.

A flamingo's pink or reddish feather, leg, and facial coloration come from a diet high in alpha and beta carotenoid pigments, including canthaxanthin. The richest sources of carotenoids are found in the algae and various invertebrates that make up the bulk of a flamingo's diet.

The shape of flamingo's filtering bill determines its diet. A flamingo will either have a shallow or a deep-keeled bill.

Slight differences in diet and habits prevent competition among flamingos that share feeding grounds.

Lesser flamingos eat an estimated 60 g (2.1 oz.) dry weight to fulfill their daily food requirements. Through slow-motion photography, researchers discovered that these birds pump water through their bills 20 times a second to filter their food.

A much slower filtration rate was found in the Caribbean flamingos - only 4 to 5 times a second to filter out their daily food requirements of 270 g (9.5 oz.) dry weight.

Standing in shallow water, flamingos lower their necks and tilt their heads slightly upside-down, allowing their bills to hang upside-down facing backward in the water.

Flamingos sweep their heads from side to side just below the surface of the water to collect their food if they have a deep-keeled mandible. If the mandible is shallow-keeled, a flamingo sweeps its head from side to side deeper into the mud to collect its food.

A flamingo filters its food out of the water and mud with a spiny, piston-like tongue that aids in sucking food-filled water past the lamellae inside the curved bill. The fringed lamellae filter out food, and the water is passed back out of the bill.

In addition to filtering food into the bill, lamellae also exclude foods that may be too large or small for the flamingo.

Standing in water, flamingos may stamp their webbed feet to stir up food from the bottom.

Flamingos are fed a varied diet in zoological environments in order to maintain their pink coloration, as well as their general health.

SeaWorld and Busch Gardens feed flamingos a diet that includes all the nutrients needed for optimal health. The flamingos are fed in a specially designed feeding trough.

Flamingos seek out fresh water for drinking.