What Eats Seaweed in Ocean? List of Seaweed-eating Animals

Seaweed is similar to other types of aquatic plants that may be found growing in various water-based environments such as rivers, seas, and lakes.  Around 12000 different types of seaweed species may be found in the globe today with abundant amounts.

Due to the huge seaweed availability, there are a great number of creatures that can exist by eating seaweed. Even though it might not look like the most appetizing meal, many marine species include seaweed as a regular part of their diet.

For certain marine organisms, seaweed accounts for more than 50% of their entire dietary intake. Let’s discuss all about seaweed and what eats seaweed in the ocean.

What animals eats seaweed?

Starfish, Shrimp, Crabs, Turtle, Betta Fish, Lobster, Eel, Sea Lion, Penguin, California, Sea Otter, Albatross, Dolphin, Angelfish, Manatee, Pufferfish and Ducks are some of the most prominent creatures/animals that eat seaweed.

What is seaweed?

There are thousands of different kinds of algae, and they are all found in aquatic habitats worldwide. Algae may be roughly categorized into two types based on their size.

  1. Large algae, sometimes known as “macro” algae, are more widely known as seaweed.
  2. Microalgae, however, are so tiny that they can only be seen with a microscope.

How it helps marine ecology?

Seaweeds are extremely important components of marine ecosystems.

They serve as the foundation of marine food chains, supplying energy and nutrients to animals by either direct consumption of the fronds or indirect consumption of the fine particles produced by decomposition and ingested by filter-feeding organisms.

It matures rapidly—some types of seaweeds may be ripe in as little as six weeks, ensuring their availability to marine life quickly.

Seaweeds also act as a helpful carbon sink because it consumes CO2 as it grows. Additionally, algae consume other surplus nutrients, such as nitrogen and phosphorus, and contribute to forming new habitats for marine life.

List of animals that eat seaweed

Here is a comprehensive list of animals that eat seaweed.


Apart from the seaweed, starfish also feast on reef coral, seagrass, algae, sea cucumber etc

Starfish are invertebrates and must stick to rocks or reefs in order to survive.

Starfish consume primarily plant-based food as part of their diet, and seaweed is the central part of it (because it is readily available).


Amano Shrimp
Seaweed is a natural diet of shrimps, they can better digest seaweed fibers than plant fibers

The vast majority of shrimp species do not prioritize seaweed regarding the food they consume. But they also eat it when no other food is available.

In most cases, shrimp will only consume seaweed if there are no other predators in the area where the seaweed is located.

When a substantial piece of seaweed is left untouched, it indicates that there is no threat of predators in the area; thus, shrimp will go in to feed on the still-present seaweed.



Most types of crabs are omnivores and can eat everything they get in their way.

Crabs also have a digestive system that consumes both plant and animal-based diets. So, seaweed serves as an excellent source of nutrition for these organisms.



As with crabs, the vast majority of turtle species are omnivores, which means they are able to derive nutrition from both plant and animal sources. The Green and Hawksbill turtles are two examples of herbivorous species of turtles.

This indicates that these turtles will only be able to survive by eating marine plants such as seaweed and other types of aquatic vegetation.

Because seaweed frequently becomes entangled in coral reefs, turtles are commonly observed in the area.

Some species of turtles, such as the Hawksbill, have a more pointed beak than others, allowing them to fit into tight spaces on reefs.

If there is no other seaweed floating near the surface, the turtles are able to use this technique to retrieve seaweed from the depths of the reefs so that they can ingest it.

Similarly, the jaws of green sea turtles are toothed, and their teeth are like saws, enabling the animal to scrape seaweed from the top of rocks.

Similarly, the jaws of green sea turtles are toothed, and their teeth are like saws, enabling the animal to scrape seaweed from the top of rocks.

Betta fish

Betta Fish

One of the kinds of fish that can eat seaweed and algae is betta fish.

However, it is necessary to provide care for these fishes (if you are keeping them in an aquarium). The fish might be given algae pellets as one of the possible solutions. These pellets are composed of the components discovered in natural seaweed.

Betta fishes get the energy needed to carry out their normal daily activities from the algae and seaweed they consume in the wild.

When it comes to the fish in the tank, on the other hand, you will need to provide them with proper amounts of minerals and vitamins in separate containers.

These pellets have the potential to assist the betta fishes in the development of a robust digestive system.

In the wild, this process would take place on its own accord, but when these fishes are produced in captivity, they need to be provided with seaweed from the outside.


Underwater Lobster
Lobsters live on seafloor where they can feast on seaweed

Lobsters eat a wide variety of foods and even scavenge for leftovers. This indicates that they will eat both plant and animal stuff in their diet.

However, because lobsters frequently congregate close to the ocean floor, you will often discover these animals feeding on the seaweed and algae that are found in this region.

It is unusual for a lobster to swim up to ingest seaweed floating on the surface of the water; therefore, scavengers play an essential part in keeping the ocean bottoms clean.

Even though they prefer an animal-based diet in which they can consume small fish such as sardines, krill, or zooplankton, lobsters are frequently seen consuming seaweed to satisfy their need for a variety of vitamins and minerals. This is the primary reason for this behavior.


Even though they focus primarily on eating tiny fish, eels sometimes consume seaweed to supplement their diet. It has been witnessed that they would wrap themselves around huge plants in order to consume the surrounding vegetation better.

Even though most eels do not really enjoy the taste of seaweed, they will resort to eating it if they have nothing else to eat. They frequently encircle bulk seaweed  and use their teeth to nip at the leaves while wrapped around the plants.

Sea Lion

One of the numerous types of creatures that love a diet consisting of seaweed is the sea lion. These marine animals feed on various types of seaweed and may be found near the beaches of both the Pacific and the Atlantic seas.

Sea lions rip apart the bits of seaweed they consume with the solid front flippers on their feet. Sea lions require additional fish, crabs, and crustaceans due to the low-calorie content of their natural diet.


Penguins are rare creatures who like eating seaweed and are included in the list of animals that consume seaweed. They eat so much of it that the guano they produce is frequently used as fertilizer.

Sea Otter

The sea otter, especially California Sea Otter, is a species of marine mammal that is indigenous to the shores of California and Mexico. The majority of the food that these otters consume consists of marine crustaceans, including crabs, mussels, and snails.

But they also enjoy nibbling on seaweed! It has been shown that sea otters consume up to 20 percent of their total weight in seaweed daily.

Otters, in contrast to the majority of other animals, who are either herbivores or omnivores, consume a significant amount of seaweed because it supplies them with nutrients that are usually present in terrestrial plants but are challenging to get in their natural environment.


The albatross is a kind of seabird that is typically spotted soaring over the waters close to Antarctica. Because their wings are so large and thin, these birds can fly effortlessly for long periods without having to flap them.

And the majority of their food is comprised of marine plants. The beaks of albatrosses are used to pick bits of seaweed from the surface of the water, consumed in their whole.

Because they lack both stomachs and teeth, it is not known how they digest the food they eat of this kind. According to scientists, the seaweed passes through the bird’s digestive tract and then exits the animal in droppings as a component of the bird’s urine.


The dolphin is the next animal on the list of those who consume seaweed. Most people believe that dolphins only consume fish, but in reality, they also eat seaweed. It has been shown that they consume more than 15 percent of their body weight in seaweed daily.

Although they mostly devour algae and other microscopic marine plants, dolphins will occasionally eat invertebrates. Even though plants make up most of their nutrition, these creatures are carnivores.


Angelfish are a type of tropical fish found across the Indo-Pacific area in relatively clean waters. They are referred to as “seahorse fish” because they are frequently found hanging from coral reefs in an inverted position. Angelfish consume different types of invertebrates, such as worms and tiny crustaceans. In addition to that, they consume a moderate quantity of marine seaweed.


Adult manatees, which belong to the animal order Cetacea, can weigh anywhere from 14 to 48 kilograms. They consume moist vegetation equivalent to between 4% and 9% of their body weight daily. The food of a manatee is made up of several types of marine grasses and seaweeds.


The puffer fish is a big, spine-backed predatory marine fish. They consume marine plants and animals such as sea urchins, crabs, fish, squid etc., in addition to the seaweed. Only puffer fish are known to possess poison glands, making them unique among fish. They kill their victims by injecting them with poisons.


Ducks are one of the waterfowl that may be found in nearly every country globally. They may be found in any body of water, whether it be coastal or inland. Ducks also consume many different things, including seaweed. They get a boost in energy from eating seaweed, which benefits them.

How does seaweed help animals?

There are several reasons why animals should consume seaweed, including the following:

Source of minerals, vitamins etc

The best source of naturally occurring components such as minerals, enzymes, vitamins and other nutrients may be found in seaweed. All these essential nutrients strengthen the immune system and provide anti-inflammatory benefits.

Fibre diet (Healthy digestion)

When it comes to animals, seaweed can assist promote digestive sensitivities. This is because it is loaded with fibre, which is known to include anti-inflammatory and anti-tumour qualities. Additionally, seaweed is loaded with prebiotics, which supports the growth of healthy bacteria in the gut of many animals.


Antioxidants play a crucial role in maintaining cardiovascular health as well as the power of the immune system as a whole. Seaweed contains various antioxidants, which can lengthen the life of your pet and reduce the likelihood that it may become ill from an illness.

Allergy assistance

Seaweed can be an excellent alternative nutrition source for animals suffering from dietary sensitivities. Consuming foods that include seaweed may help alleviate symptoms of roughness and redness of the skin.


A wide variety of marine animals consume seaweed, including crabs, dolphins, sea otters, sea lions, sea turtles, lobsters etc.

In contrast to popular belief, seaweed is not a kind of plant at all. Although it appears like one, it doesn’t have roots like a plant. Seaweed is, in fact, macro algae growing in rivers, lakes, and seas.