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Fish vs. Amphibians — What's the Difference?

By Tayyaba Rehman & Urooj Arif — Published on May 7, 2024
Fish are aquatic vertebrates with gills and fins, living exclusively in water. Amphibians are vertebrates that live in water during their larval stage and on land as adults, breathing through lungs and skin.
Fish vs. Amphibians — What's the Difference?

Difference Between Fish and Amphibians


Key Differences

Fish are aquatic creatures that have specialized organs called gills, which they use to breathe underwater. Their bodies are designed for life in water, with streamlined shapes and fins for swimming. Fish reproduce in a variety of ways, but most lay eggs in the water. They are ectothermic, or cold-blooded, meaning their body temperature varies with the environment.
Amphibians, on the other hand, begin their life cycle in water and often move to land as they mature. They have lungs for breathing air as adults, although some species also use their skin for gas exchange. Amphibians typically undergo a metamorphosis from a larval stage to an adult form, changing their habitat and sometimes their diet. They are also ectothermic but rely on both water and land environments to complete their life cycle.
While fish are covered in scales that protect their bodies, amphibians have permeable skin that can absorb water and oxygen, which is why they often stay near moist environments. This skin requires them to live in habitats that will not dry them out, limiting their range compared to fish.
Fish have a wide variety of reproductive strategies, including laying eggs (oviparous), giving birth to live young (viviparous), and a combination of both (ovoviviparous). Their reproductive behavior can be quite complex, involving courtship and sometimes parental care of the eggs or young.
Amphibians usually lay their eggs in water, and these eggs are often unprotected by a hard shell, making them susceptible to dehydration. This necessitates a moist environment for successful reproduction. The transition from water to land as they develop allows for a unique life cycle that impacts their feeding, breeding, and habitat preferences.

Comparison Chart


Aquatic (freshwater and marine)
Aquatic and terrestrial


Lungs and skin


Permeable and moist


Mostly oviparous
Mostly oviparous with aquatic eggs

Body Temperature


Life Cycle

No metamorphosis
Undergo metamorphosis

Example Species

Salmon, trout
Frogs, salamanders

Breeding Environment

Water (larval stage)

Adult Lifestyle

Mostly terrestrial

Compare with Definitions


Aquatic vertebrates with gills and usually fins and scales.
The salmon swam upstream to spawn.


Vertebrates that live both on land and in water at different life stages.
Frogs are amphibians that lay their eggs in water.


Cold-blooded animals living exclusively in water.
The aquarium housed tropical fish from around the world.


Breathe through lungs as adults and through skin.
Salamanders absorb oxygen through their moist skin.


Species that lay eggs, with few giving birth to live young.
Many fish release thousands of eggs in the hopes a few will survive.


Undergo metamorphosis from larval to adult stage.
The tadpole transformed into a frog over a few months.


Predominantly breathe through gills.
Fish extract oxygen from water passing over their gills.


Lay eggs in moist environments to prevent drying out.
The female salamander laid her eggs in a damp underbrush.


Have a diverse range in size and habitat.
Fish can range from tiny guppies to massive sharks.


Depend on aquatic habitats for breeding.
Amphibians return to the water to reproduce, even if they live mostly on land.


To catch or try to catch fish in
Fish mountain streams.


An animal capable of living both on land and in water.


An oviparous, vertebrate animal usually having fins and a covering scales or plates. It breathes by means of gills, and lives almost entirely in the water. See Pisces.


Plural of amphibian


Catch or try to catch fish or shellfish;
I like to go fishing on weekends

Common Curiosities

Can amphibians breathe underwater?

Amphibians can breathe underwater in their larval stage but rely on lungs and skin as adults.

How do amphibians' skin differ from fish?

Amphibians have moist, permeable skin for gas exchange, whereas fish have scales.

What is metamorphosis in amphibians?

It's the process where they transform from water-dwelling larvae to land-dwelling adults.

What types of habitats do amphibians need?

They need both aquatic for breeding and moist terrestrial habitats for living.

Do all fish lay eggs?

Most fish lay eggs, but some species give birth to live young.

What role do fish play in the ecosystem?

They are crucial for aquatic food webs, serving as both predators and prey.

Can amphibians live in marine environments?

Most amphibians are freshwater and terrestrial; very few can tolerate brackish environments.

Do fish undergo metamorphosis?

Fish do not undergo metamorphosis; their development is direct.

What distinguishes fish from amphibians?

Fish are aquatic and breathe through gills, while amphibians live in both water and land and breathe through lungs and skin.

How do fish breathe?

Fish breathe by passing water over their gills to extract oxygen.

Why are amphibian populations declining?

Due to habitat loss, pollution, disease, and climate change.

How do amphibians contribute to biodiversity?

As predators and prey, they are key to both aquatic and terrestrial ecosystems.

Can amphibians absorb water through their skin?

Yes, their permeable skin allows for water and gas exchange.

Are there amphibians that can live without water?

While all need moisture for their skin, some desert species minimize water loss remarkably.

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Author Spotlight

Written by
Tayyaba Rehman
Tayyaba Rehman is a distinguished writer, currently serving as a primary contributor to As a researcher in semantics and etymology, Tayyaba's passion for the complexity of languages and their distinctions has found a perfect home on the platform. Tayyaba delves into the intricacies of language, distinguishing between commonly confused words and phrases, thereby providing clarity for readers worldwide.
Co-written by
Urooj Arif
Urooj is a skilled content writer at Ask Difference, known for her exceptional ability to simplify complex topics into engaging and informative content. With a passion for research and a flair for clear, concise writing, she consistently delivers articles that resonate with our diverse audience.

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