What Marine Animals Are Herbivores?

Updated July 19, 2017

Home to millions of plants and animals, the ocean offers a wide range of creatures. These animals are broken into three categories: carnivores, herbivores, and omnivores. Carnivores are predators that eat meat. Herbivores eat only plants -- including algae and sea grasses. The omnivore eats both meat and plants. Very few marine animals are herbivores.


Part of the herbivorous order called Sirenia, manatees are found in the warm coastal waters of the Atlantic Ocean. An adult manatee's weight ranges from 200 Kilogram to 590 Kilogram. Manatees have a broad flat tail shaped like a flipper. Swimming at a rate of 5 to 15 miles per hour, manatees are slow, graceful creatures. They consume 10 per cent of their body weight in sea grass and freshwater vegetation every day. Surfacing every three to four minutes for air, their days consist of eating and sleeping. Manatees live for roughly 40 years. Protected by law, manatees are on the endangered list.


Indigenous to the coast of the Indian and Pacific Oceans, the dugong is related to the manatee. Weighing anywhere from 231 Kilogram to 499 Kilogram, the dugong has a body that is shaped like a grey spindle with no dorsal fin. Dugongs differ from manatees only in their tail structure. Dugong's tails are forked, similar to the fork of a whale or shark tail. Preferring shallow, calm waters, they graze on sea grass and algae throughout the day and night. They can stay underwater for six minutes before they must surface to breathe. Placed on the endangered species list in 1970, this species is still threatened due to boating collisions.

Green Sea Turtle

Named for its skin colour, the green sea turtle can be found in the tropical and subtropical regions around the globe. One of the largest populations is found in Hawaii. Weighing up to 318 Kilogram, the turtle has a smooth brown shell that spans five feet. Its head is non-retractable, meaning that the turtle cannot pull it back into their shell. Adult green sea turtles feed on sea grasses and algae. Occasionally, juvenile sea turtles will eat jellyfish and sponges, but their main diet consists of underwater vegetation. These turtles are on the critically endangered list due to boating and fishnet accidents.

Parrot Fish

Living in the tropical reef areas of the ocean, the parrot fish has a mouth and colouring that resemble those of its namesake. The fused jaws of a parrot fish form a parrot-like beak. Scraping algae and bits of coral off the reef, the parrot fish grinds the food up and spits out the hard coral fragments. Brightly coloured in shades of blue, green and yellow, it can change colours and genders as it grows. Part of the Scaridae family that comprises more than 80 species, the parrot fish can grow as large as four feet long and weight up to 20.4 Kilogram.

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About the Author

Lisa Roberts embarked on a writing career after 10 years in human resources. She holds a bachelor's degree in human resources and marketing from Baylor University and has worked in the education field for more than 12 years.