Anhingas and Cormorants are sometimes confused with each other, but Anhingas have a long sharp beak, while Cormorants have a curved beak and a stockier body. Cornell All About Birds says:

ANHINGAS: "A dark body stealthily swims through a lake with only a snakelike head poking above the surface. What may sound like the Loch Ness monster is actually an Anhinga, swimming underwater and stabbing fish with its daggerlike bill. After every dip, it strikes a regal pose on the edges of shallow lakes and ponds, with its silvery wings outstretched and head held high to dry its waterlogged feathers. Once dry, it takes to the sky, soaring high on thermals stretched out like a cross. The Anhinga's distinctive shape earned it the nickname "water turkey" for its turkeylike tail, and "snake bird" for its long snakelike neck as it slithers through the water. Unlike most waterbirds, the Anhinga doesn't have waterproof feathers. While that may seem like a disadvantage for their watery lifestyle, their wet feathers and dense bones help them slowly submerge their bodies under the water so they can slyly stalk fish. The name Anhinga comes from the Tupi Indians in Brazil, meaning "devil bird" or "evil spirit of the woods."

DOUBLE CRESTED CORMORANTS: "The gangly Double-crested Cormorant is a prehistoric-looking, matte-black fishing bird with yellow-orange facial skin. Though they look like a combination of a goose and a loon, they are relatives of frigatebirds and boobies and are a common sight around fresh and salt water across North America—perhaps attracting the most attention when they stand on docks, rocky islands, and channel markers, their wings spread out to dry. These solid, heavy-boned birds are experts at diving to catch small fish. From a distance, Double-crested Cormorants are dark birds with snaky necks, but up-close they’re quite colorful—with orange-yellow skin on their face and throat, striking aquamarine eyes that sparkle like jewels, and a mouth that is bright blue on the inside. Cormorants often stand in the sun with their wings spread out to dry. They have less preen oil than other birds, so their feathers can get soaked rather than shedding water like a duck’s. Though this seems like a problem for a bird that spends its life in water, wet feathers probably make it easier for cormorants to hunt underwater with agility and speed."