What is the difference between a fish and dolphins?

While both fish and dolphins live in water and have a streamlined body shape, they are very different creatures with distinct characteristics. Here's a breakdown of their key differences:

Fish:

* Class: Pisces

* Respiration: Breathe through gills, extracting oxygen from the water.

* Body Covering: Covered in scales.

* Reproduction: Lay eggs.

* Skeletal Structure: Have a bony or cartilaginous skeleton.

* Limbs: Possess fins for swimming.

* Warm/Cold Blooded: Cold-blooded, meaning their body temperature fluctuates with the environment.

* Examples: Salmon, tuna, shark, catfish, goldfish.

Dolphins:

* Class: Mammalia

* Respiration: Breathe air through lungs.

* Body Covering: Have smooth skin.

* Reproduction: Give birth to live young.

* Skeletal Structure: Have a bony skeleton.

* Limbs: Have flippers and a tail fluke for swimming.

* Warm/Cold Blooded: Warm-blooded, meaning they maintain a constant body temperature.

* Examples: Bottlenose dolphin, humpback dolphin, river dolphin.

In summary:

* Fish are aquatic animals that breathe through gills and have scales.

* Dolphins are marine mammals that breathe air through lungs and have smooth skin.

This fundamental difference in breathing systems is the key distinction that separates fish from dolphins and highlights their distinct evolutionary paths.