What Eats Seaweed? 9 Seaweed Eating Animals!

Last updated on October 19th, 2022

What animals eat seaweed? This is the question on every marine biologist’s mind.

The ocean is full of amazing creatures, and several of these creatures have varied eating habits. An oceanographer friend recently gave me an insight into the eating habits of several sea animals.

He was working on animals living near the coral reefs of Australia, where he studied creatures that would consume algae and seaweed.

As we got talking, I understood that these creatures helped protect the coral reefs by consuming the algae. Just as we need to clean our swimming pools regularly to keep them free of moss, the oceans also need to be cleaned.

Just as I found out what eats seaweed I learned that these creatures consume the algae allowing the coral reefs to breathe. The animals that eat seaweed keep the ocean clean and unclogged in a manner of saying.

Animals that eat seaweed:

  • Crab
  • Shrimp
  • Turtle
  • Pufferfish
  • Starfish
  • Bettafish
  • Krill
  • Lobster
  • Eel

This unusual anecdote further above got me thinking, and with his help, I made this list to take a closer look at the animals that eat seaweed.

List of ocean animals that eat seaweed:

1. Crab

crabs on seaweed rocks 15012022

It has been documented that there are over 4500 different species of crabs across the world, and most of these crabs are omnivores.

Most crabs live in the sea, which is why when you visit the beach, you might see crabs scuttling along the sands.

Crabs consume worms, shrimps, small fishes, and even algae or seaweed.

Research has shown that with the ongoing devastating effects of climate change, many coral reefs are getting clogged and dying due to the accumulation of seaweed.

But the reefs where there are more crabs, the accumulation of seaweed near the reefs has reduced significantly.

It is because the crabs consume the seaweed and help the corals to breathe.

2. Shrimp

shrimp and seaweed 15012022

Shrimps are not quickly drawn towards seaweed, but these tiny creatures will consume seaweed near the ocean floor.

This means shrimps will not go looking for seaweed, but they will choose to consume ocean algae if no other creatures are seen consuming it.

Certain shrimps like the red cherry shrimp are known to love seaweed. One of the reasons shrimps will consume seaweed if it is left unconsumed by other creatures is the lack of predators near the seaweed.

Once a colony or a troupe of shrimp has identified a suitable amount of seaweed, they will nibble at it and consume the entire algae in minutes.

Thus, shrimps play a crucial role in keeping the ocean floor clean and free of seaweed.

3. Turtle

turtle and seaweed 15012022

Most turtles are omnivores, meaning they can survive on plant and animal-based diets. But specific turtles like the Green and the Hawksbill are herbivores.

This means these turtles will survive only on algae, seaweed, and other plants found in the ocean.

Turtles are often found near coral reefs as seaweed often gets stuck around the reefs.

Some turtles like the Hawksbill have a narrow beak that allows the creature to dig into the reef’s crevices.

This allows the turtles to pull out the seaweed from the depth of the reefs to consume if no other seaweed is floating near the surface.

Similarly, the mouths of green sea turtles are serrated and have teeth like saws which allow the creature to scrape the algae or seaweed from the surface of the rocks.

4. Pufferfish

pufferfish and seaweed 15012022

The diet of pufferfishes includes invertebrates and algae primarily. So if you have marine pufferfish in your aquarium, it is good to give the creature algae as part of its diet.

When you give algae to marine pufferfishes, you should give algae rounds or pellets. These have all the natural minerals and ingredients found in natural algae.

As algae or seaweed eaters, pufferfishes need Vitamin C and many other minerals to prevent them from losing body mass.

The creature can easily supplement its requirement in the ocean by consuming seaweed.

But if you have a pufferfish in your aquarium, you need to give it algae pellets to ensure that it gets its supply of Vitamin C and minerals.

5. Starfish

starfish and seaweed 15012022

Starfishes are known to consume all types of plant matter.

You will find these creatures adhered to rocks or on the ocean floor consuming different types of plant matter like kelp, algae, seaweed, and even decomposing animal matter.

Starfishes tend to keep the ocean clean and prevent the clogging of the coral reefs.

You will often find that starfishes consume live and decomposing plant matter from the ocean floor as well.

Starfishes can survive exclusively on algae and seaweed. However, they tend to consume sea urchins when they come across them.

Seaweed that gets caught in the coral reefs can be consumed by starfishes easily, which is why starfishes are essential for the survival of the coral reefs.

6. Betta fish

betta fish and seaweed 15012022

Betta fishes are one of the species of fish that can consume algae and seaweed. They can adorn your aquarium and make it look attractive.

But caring for these fishes is essential. One of the ways would be to give the fish algae pellets. These pellets consist of the ingredients found in natural seaweed.

In the wild, betta fishes consume algae and seaweed as a source of energy to go about their daily activities.

But when it comes to the fish in the aquarium, you need to supply adequate minerals and vitamins separately.

These pellets can also help the betta fishes develop a robust digestive system.

This process would occur naturally in the wild, but when these fishes are bred in captivity, they need to be supplied with seaweed externally.

7. Krill

krill 15012022

Krills are small crustaceans that are found in all oceans across the world. You will even find krills in the cold waters of the Antarctic and Arctic.

These tiny creatures are known to thrive even in the most extreme conditions.

Krills consume several types of plant matter that are found in oceans.

These creatures can even consume the plankton and seaweed found beneath the ice in the Arctic and Antarctic.

Research shows that krill can survive on phytoplankton, zooplankton, algae, and common seaweed.

If a colony of krill finds seaweed floating on the sea’s surface, they can swim up to consume these.

This means that krills not only consume the algae found near the ocean floor but also on the surface.

8. Lobster

lobster and seaweed 15012022

Lobsters are omnivores and scavengers. This means they will consume plant and animal matter.

But as lobsters tend to stay near the ocean floor, you will find these creatures consuming the seaweed and algae that grow near the bottom of the sea.

Scavengers play a crucial role in keeping the ocean beds clean and rarely will a lobster swim up to consume the seaweed floating on the surface.

Although lobsters prefer an animal-based diet where they can consume small fish like sardines, minnows, or zooplankton, they are often found consuming seaweed primarily to supplement their requirement for different vitamins and minerals.

9. Eel

electric eel hunting fish 10102021

Most eels are omnivores, and they can survive on an animal and a plant-based diet. Among the several eel species, the gulper eel survives only on a plant-based diet.

These creatures are known to consume seaweed, plankton, as well as algae. You will often find eels around coral reefs digging into crevices for seaweed.

The eels can swim to the depths of the ocean in search of food, and they can consume the seaweed growing on the ocean floor as well.

A recent study shows that Moray eels, primarily carnivorous, can consume large amounts of kelp and seaweed.

With the help of particular chemical tracing, an isotope was isolated in the Moray eels found in Kelp. This helped scientists conclude that eels too eat seaweed.

Aside from the seaweed-eating animals, we have compiled a list of animals that eat moss here.

What animals eat seaweed?

The ocean animals that eat seaweed are crabs, shrimps, turtles, pufferfish, starfishes, betta fish, krill, lobsters, and eels. However, seaweed is one of those water plants that marine-based creatures will consume when other food sources are scarce.

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