What is the genus for fish?

There is no single genus for all fish. "Fish" is a very broad category, encompassing thousands of species across many different taxonomic groups.

Here's why:

* Fish are not a single, unified group: They are a diverse collection of aquatic vertebrates with gills and fins, representing a wide range of evolutionary paths.

* They are classified into different classes: Fish are broadly divided into three major classes:

* Agnatha: Jawless fish like lampreys and hagfish.

* Chondrichthyes: Cartilaginous fish like sharks, rays, and skates.

* Osteichthyes: Bony fish, which includes the vast majority of fish species.

* Each class further divides into orders, families, genera, and species: Within each class, there are many orders, families, genera, and species.

For example:

* Salmon: Belongs to the genus *Salmo*.

* Tuna: Belongs to the genus *Thunnus*.

* Clownfish: Belongs to the genus *Amphiprion*.

So, to identify the genus of a particular fish, you need to know the specific species you're interested in.