What Animals Eat Algae? A Full List And Details

I didn’t think much about animals eating algae before researching this vast food source. I learned that algae are an important food source for many animals, but not all. If you’re curious about which creatures enjoy algae as a part of their diet, read on to find out more about the types of animals that eat algae and how they use it.

Aquatic animals that eat algae

  • Snails
  • Crabs
  • Sea Urchins
  • Sea Cucumbers
  • Frogs
  • Goldfish
  • Flagfish
  • Algae Eaters
  • Shrimp

Birds that eat algae

  • Duck
  • Coot
  • Gadwall
  • Scoter
  • Sora

Algae can be found in fresh water or saltwater environments (or both). They exist as microscopic bacteria-like organisms or single and multi-cellular forms, and can be either green, brown, red, or even purple.

Many different types of animals eat algae including: mollusks, crustaceans, fish, sea urchins, abalone, and various other types of invertebrates as well as larger fish (such as Lingcod, Halibut, Rockfish, Snapper, and various types of Mackerel). Waterbirds are also know to eat algae including ducks and gadwalls.

Algae are actually one of the most abundant organisms on Earth. They live in both fresh water and salt water environments, while also inhabiting soil and leaf litter. As such, there’s no shortage of different types of algae to be found in nature. There are three main groups: green algae (Chlorophyta), brown or golden-brown algae (Phaeophyta), and red or purple bacteria (Rhodophyta). Green Algae is the largest group of algae and contains more than half of all known species.

Mollusks that eat algae

Mollusks eat green algae because it’s a readily available food source.

There are several different types of mollusk that eat algae, including: limpets and chitons (both of these gastropods graze on Ulva), the common whelk (whelks eat kelp), and abalone (abalone feed on red algae).

Crustaceans that eat algae

Crustaceans also enjoy eating algae. Copepods eat both green and brown algae, while the sea urchin (a type of echinoderm), blue mussels, hermit crabs, and sand hoppers also feed on them in some cases.

Fish that eat algae

Fish such as the garibaldi and kelp bass prey upon animals that eat Ulva or kelp.

Larger fish such as the Lingcod and Halibut eat green algae as well, but primarily feed on fish that find their food thanks to green algae.

Green Algae (Chlorophyta): 

There are many different types of green algae, including both single-cell and multi-cellular algae. The most common type of green algae is Ulva, which can be found attached to rocks in tidal pools. Kelp is another type of green seaweed that is eaten by many animals.

Brown or Golden-brown Algae (Phaeophyta) :  

Algae in this group are often referred to as kelp because of their resemblance to true kelp. This group is mainly made up of large seaweeds that can grow very tall, forming underwater forests in some cases. One example of brown algae is Macrocystis. This type of algae has air bladders that make it float on the surface, allowing it to absorb sunlight more easily and grow even taller than other types of seaweed.

Animals that eat brown algae include: sea urchins, abalone, and a wide variety of fish such as the Lingcod, Halibut, Greenlings, various types of Snapper, and Rockfish among others.

Red or Purple Bacteria (Rhodophyta) :  

Red or purple bacteria are microscopic organisms that can be found in both fresh and salt water. The red or purple color comes from the pigment phycoerythrin, which serves as a sunscreen for the bacteria.

Animals that eat this type of algae are really just eating phycoerythrin itself, rather than ingesting actual cells. Snails are especially fond of these types of algae and will eat red bacteria in addition to green and brown algae.

Red or purple bacteria are also eaten by krill, which in turn are a popular food source for various types of whales.