What are the different kinds or types of fish?

It's impossible to list *all* the different kinds of fish because there are over 33,000 known species! However, we can classify them into broader categories based on different characteristics:

By habitat:

* Freshwater: Live in rivers, lakes, ponds, and streams. Examples include trout, catfish, bass, and goldfish.

* Saltwater: Live in oceans and seas. Examples include tuna, sharks, salmon, and jellyfish.

* Brackish: Live in areas where fresh and saltwater mix, like estuaries. Examples include flounder, mullet, and striped bass.

By body shape:

* Fusiform: Torpedo-shaped body, efficient for swimming. Examples include tuna, marlin, and mackerel.

* Compressed: Flattened body, good for maneuvering in tight spaces. Examples include flounder, halibut, and skate.

* Depressed: Flattened top-to-bottom, good for resting on the seabed. Examples include rays, skates, and some sharks.

* Eel-like: Long and slender body, good for burrowing and squeezing through narrow spaces. Examples include eels, moray eels, and lampreys.

By feeding habits:

* Carnivores: Eat other animals. Examples include sharks, barracuda, and pike.

* Herbivores: Eat plants. Examples include parrotfish, surgeonfish, and some carp species.

* Omnivores: Eat both plants and animals. Examples include catfish, goldfish, and some sharks.

* Filter feeders: Strain food particles from the water. Examples include whales, baleen whales, and some types of plankton.

By skeletal structure:

* Bony fish: Have a bony skeleton. Examples include tuna, salmon, and bass.

* Cartilaginous fish: Have a skeleton made of cartilage. Examples include sharks, rays, and skates.

* Jawless fish: Lack jaws and have a skull made of cartilage. Examples include hagfish and lampreys.

By reproduction:

* Oviparous: Lay eggs. Examples include most bony fish, sharks, and rays.

* Viviparous: Give birth to live young. Examples include some sharks and rays.

By other characteristics:

* Deep-sea fish: Live in the depths of the ocean, often with adaptations for low light and high pressure.

* Freshwater fish: Live in rivers, lakes, and ponds.

* Saltwater fish: Live in oceans and seas.

* Tropical fish: Live in warm, shallow waters.

* Coldwater fish: Live in colder waters.

* Game fish: Popular for fishing.

* Ornamental fish: Kept in aquariums.

This list is not exhaustive, and there is much more to learn about the amazing diversity of fish in the world.