What Eats Zooplankton? (11 Animals +Pictures)

what eats zooplankton
Image: Zooplankton under a microscope

Animals that eat zooplankton include whales, fish, shrimp, snails, jellyfish, and clams.

Zooplankton are instrumental in maintaining and supporting the marine life food web.

They have many predators that prey on them for survival, including small fish residing in temperate and polar waters. The defense strategy for zooplankton entails feeding on shallow water at night and migrating into deeper and darker waters before shallow water predators start hunting.

Regardless of this defense strategy, they are still preyed on. The main predators of zooplankton are small fish.

What Eats Zooplankton? 7 Top Predators

1. Menhaden

Menhadens are found in large schools that can extend up to 40 miles. They are a sub-species of the herring family and are significantly small.

They are excellent ocean swimmers that feed on zooplankton collected as they swim. They are called filter feeders since they filter zooplankton collected through their gill rakers.

An adult menhaden can collect around 4 gallons of zooplankton-filled water in a minute. It then filters the water through its gills and retains the zooplankton that present essential survival nutrients.

2. Silver Carp

Silver carp are native to China and were introduced in the United States to control algae in agricultural fish farms. However, they found their way into American waters.

Like the menhaden, silver carp are also filter feeders with the capabilities of filtering phytoplankton. Its special filtration capability is enhanced by a sponge-like gill raker with sticky mucus secreted by the gills.

The enhanced filtration capacity is a threat to the ecosystem as this fish can filter in almost everything it collects. Thus leaving little for other fish that survive on zooplankton.

3. Capelin

Capelin are found in the Arctic and Atlantic Oceans. They are tiny fish of the smelt family that prey on zooplankton.

Capelin have large mouths and developed gills that allow them to feed on zooplankton. The type of zooplankton that the capelin prefers depends on the size of the fish. Smaller capelins prefer to feed on copepods, while larger capelins prefer krill.

It prefers to feed at the edge of the ice shelf. They are considered the main grazers of zooplankton in the ocean.

4. Snails

Snails are excellent zooplankton eaters. The pond snail and the ramshorn snail are the best at feeding on zooplankton because they remain relatively small throughout their life.

5. Shrimp

Among shrimp, the best for eating plankton is the Amano shrimp. Because of this, many people will get amano shrimp to improve the attractiveness of their tank or pond.

6. Clams

Freshwater clams are the best zooplankton consumers in the clam family. However, they do not add beauty to a fishtank since they hide in the substrate.

7. Jellyfish

Jellyfish are gelatinous animals that are made of jelly-like material. They are planktons, but they are not excellent swimmers as the other planktons. They rely heavily on ocean currents to navigate.

Depending on the species, they can live in a wide range of water temperatures and depths. Therefore, they can feed on zooplankton in shallow waters and even those migrating to deep waters during the day.

Due to their small size, zooplankton cannot move against ocean currents. Therefore, jellyfish feed on them by floating with zooplankton. They use their stinging tentacles to capture their prey, predominately zooplankton.

After capturing its prey, the jellyfish uses its tentacle to move it to the mouth and swallow it whole. Jellyfish do not have teeth and digestive organs. The prey is digested inside the body cavity.

Algae and seaweed belong to a group of zooplankton and jellyfish feed on all zooplankton. Therefore, it will still feed on algae and seaweed.

Some other fish that feed on zooplankton include pufferfish, fan worm, and butterflyfish.

Related Article: 15 Examples of Animals Without Brains

8. Baleen Whales

It’s commonly believed that all whalse eat plankton, but not all whales actually eat zooplankton. For example, sperm whales prefer to eat large animals like squid and ingestion of zooplankton by sperm whales is only incedental.

One animal species that does actively eat zooplancton are Baleen Whales. They also eat krill and fish in large quantities.

9. Rainbowfish

Rainbowfish eat insects, larvae, zooplankton, and phytoplankton. These popular tropical aquarium fish are found wild in northeastern Australia, New Guinea, some islands of Indonesia, Sulawesi and Madagascar.

Rainbowfish aren’t the only pet fish that will eat plankton. The very popular tetra fish also loves to consume plankton. However, most fish owners feed their fish specialized fish food, so most fish in captivity tend not to have plankton as their diet.

10. Gizzard Shad

The gizzard shad is a member of the herring family and native to United States waters. They prefer to stay in freshwater lakes, streams, and rivers, but they are also found on the Atlantic coast of the United States.

They are planktivorous during their early stages of the lifecycle, predominately feeding on zooplankton. However, in most natural lakes, gizzard shad survive on zooplankton their entire life.

But if instance where they are many, especially in Midwestern United States reservoirs, they shift from exclusively relying on zooplankton and shift to diets with sediment detritus.

Zooplankton have superior nutritional values to gizzard shad compared to detritus, and thus if the availability of zooplankton is not limited, they prefer to feed on them throughout their lives.

Gizzard shad prefer to feed during the day, but they also feed at night.

11. Arrow Worm

These are tiny animals that resemble the fish due to their streamlined body, fins on both sides, and tail fin. Arrow worm uses a mass of chitinous hooks located on its head to grab and poison its prey. The poison paralyzes it.

They are voracious zooplankton predators and can detect vibration in the water similarly to a fish. They are usually transparent and remain in motion in the water, thus enhancing their camouflage. Arrow worms rely on the element of surprise to capture their prey, including copepods and appendicularians.

It is a fast swimmer, and a quick flick of its tails gives a quick dash to capture its prey with its mouth. Arrow worms do not chew their prey; rather, they swallow them whole. They are called generalist feeders because their transparent stomach reflects the community captured by plankton nets.

Are Zooplanktom on the Bottom of the Food Chain?

The marine food chain is a complex system. At the bottom of the food chain are small microscopic plants that our naked eyes cannot see, referred to as phytoplankton. The next small organism is the zooplankton, with some being microscopic and others being visible by our naked eyes.

Zooplankton are small floating animals that mainly drift the ocean. They comprise mainly copepods and make up most of the ocean animal population. They are considered the link between the predation cycles from the lowest food chain to the top predators.

They are categorized into two main groups, including holoplankton and meroplankton. Holoplanktons are zooplankton that spend their whole life as plankton, including rotifers and copepods. Meroplankton only spends a short time as planktons before evolving into other creatures such as crustaceans and larval fish.

Conclusion

Zooplankton are important in the marine food chain as they serve as an intermediary species. The disappearance of zooplankton in the marine ecosystem can be catastrophic to marine life and humans. This is due to an increased level of carbon in the air.

Furthermore, being an intermediary species in the food chain, they aid in transferring energy from primary producers to larger invertebrate predators.

Other zooplankton consumers include the feeding anemones commonly found on temperate waters. A list of plankton eaters that can be used on your tank include whiptails, stick catfish, pygmy suckermouths, siamese algae eater, Florida flagfish, and stone lapping fish.

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