Similarities Between Jellyfish and Fish

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Looking at them can make you wonder: What are these strange-looking creatures? Despite their name, jellyfish aren’t actually fish. They are unique sea creatures that are often mistaken for fish because of their name, but they have a very different structure and way of life. Although there are some key differences between the two, we’ll rather talk about the similarities between jellyfish and fish.

Read on to learn more!

What is a jellyfish?

Despite getting so much attention, many people are still not sure exactly what jellyfish are. They are soft, bell-shaped creatures with long, stinging tentacles that trail below them. You can call them animals, but they lack recognizable body parts like a face and bones. In fact, jellyfish are invertebrates, which means they do not have a vertebral column or spine. It’s not a fish because it lacks bones, scales, or fins. Instead, jellyfish drift in the water and use their tentacles to catch small prey.

Jellyfish are almost see-through and can come in various colors. Surprisingly, they are among the world’s most plentiful animals. They have more than 200 species, and the largest is the lion’s mane jelly, which can grow up to 8 feet across.

What is a fish?

A fish is a vertebrate organism that swims and lives in water. All fish have certain things in common: they have a streamlined body with fins for swimming and are covered in scales that protect their skin. Fish breathe by extracting oxygen from the water through gills, which are specialized organs for this purpose. They come in various shapes, sizes, and colors, adapted to their specific aquatic environments. Fish are cold-blooded, meaning their body temperature matches their surroundings.

Most fish are also cold-blooded, which means the temperature of their body changes with the temperature of the surrounding water. Many fish lay soft eggs, and from the eggs hatch tiny fish called larvae. The larvae then grow and form into young fish.

Similarities between Jellyfish and Fish

Similar Anatomy

Despite their distinct classifications, jellyfish and fish share some common anatomical features. Both have bilateral symmetry, meaning their bodies are symmetrical on both sides. They also possess a basic body plan consisting of a head (or bell in the case of jellyfish), body, and appendages. Additionally, both groups of animals have a simple nervous system and sensory organs to sense their surroundings.

Aquatic Creatures

Both jellyfish and fish are aquatic creatures, and their lives are intimately tied to water. They both rely on water for respiration, with fish using gills and jellyfish diffusing oxygen through their thin, gelatinous bodies. Water is also essential for buoyancy, allowing both jellyfish and fish to move and navigate their underwater habitats effectively. Additionally, these creatures are adapted to the specific conditions of their aquatic homes.

Similar Predatory Behavior

Both jellyfish and fish are predators in their respective ecosystems. Fish are well-known hunters, with various species employing different strategies, such as ambush predation, pursuit predation, or filter feeding. On the other hand, jellyfish are also carnivorous, using their long, stinging tentacles to capture prey. While their hunting mechanisms differ, both are important in maintaining the balance of aquatic food webs.

Reproduction and Life Cycle

Jellyfish and fish have complex life cycles involving multiple stages. Both typically begin as larvae, which are tiny, free-swimming organisms. These larvae then develop into juvenile forms before reaching adulthood. In the case of fish, they often exhibit diverse reproductive strategies, including external fertilization or internal fertilization, depending on the species. Jellyfish, too, undergo intricate life cycles involving polyps and medusa stages.


While jellyfish and fish belong to separate biological groups, they exhibit remarkable similarities in their anatomy, predatory behavior, and complex life cycles. They share similarities in how they adapt to aquatic environments. These parallels highlight the fascinating ways in which different species can evolve and adapt to their surroundings, shaping the rich tapestry of life in the vast oceans. Although jellyfish are unique sea creatures that are often mistaken for fish because of their name, they have a very different structure and way of life.


What are the similarities and differences between jellyfish and goldfish?

Both jellyfish and goldfish are aquatic animals that live in water. However, they differ significantly in terms of their anatomy, behavior, and classification. Goldfish belong to the group of bony fish (Osteichthyes), while jellyfish are part of the phylum Cnidaria. Goldfish have fins, scales, and a backbone, whereas jellyfish lack these features.

In what ways do you think jellyfish are similar to and different from most other fish?

Jellyfish share some commonalities with other fish in their aquatic habitat, such as relying on water for respiration and being part of aquatic food webs. However, most other fish have a backbone (vertebral column), scales, and fins, which jellyfish lack. Additionally, jellyfish are not classified as true fish; they belong to a different branch of the animal kingdom called Cnidaria.

Are jellyfish related to fish?

No, jellyfish belong to the phylum Cnidaria, which includes creatures like corals and sea anemones. Fish, on the other hand, belong to the subphylum Vertebrata within the phylum Chordata.

What is the relationship between jellyfish and small fish?

Some small fish, like certain species of juvenile fish, may seek shelter among the tentacles of jellyfish to protect themselves from predators. However, jellyfish also prey on small fish and plankton, so their relationship can be both protective and predatory, depending on the context.

Are jellyfish and starfish similar to fish?

They belong to different phyla within the animal kingdom. Jellyfish belong to Cnidaria, as mentioned earlier, while starfish are part of the phylum Echinodermata. Neither group has the characteristics that define fish, such as having a backbone and scales. So, in terms of classification, jellyfish and starfish are not similar to fish.

Author: Sagar Khillar

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