Taxonomy of Finfish

Frequently asked questions in fish taxonomy

What is the oldest class of fish, as a class?

The most primitive group of fishes alive today are the Agnatha which includes hagfishes and lampreys. These fishes donot have r developed biting jaws, like humans. They are bottom dwellers, slimy, completely lack scales of armor, and are long and eel-like. Lineages from which these fish were derived date back to the Paleozoic. Ancestral hagfish and lampreys date to the Carboniferous period, 350,000,000 years ago. They are used to explain the evolutionary processes that have lead to the more advanced forms of fish we see today.

How many fish species are there?

There are approximately 27,300 species of fishes described by science. Estimates of the actual diversity of fishes vary, although many agree that in total there are probably about 32,500 different kinds of living fishes.

What is the world's largest fish?

The largest fish in the world is the whale shark, Rhiniodon typus. It can grow to more than 50 feet in length. The second largest fish is the basking shark (Cetorhinus maximus) which can grow up to 45 feet in length.

What is the world's smallest fish?

The gobid, Trimmatom nanus is the smallest fish in the world which lives among the coral reefs of the Indo-west Pacific. The scientific name of this fish is . It grows to only 1 cm in length.

Why do scientists classify fish?

The common names of fish vary from place to place and this makes it very difficult for people to differentiate among species. For example, blacktip sharks are called "common blacktip shark" in Australia and "requiem shark" in the United Kingdom. A uniform naming system a much easier system to differentiate among species regardless of how many common names they have.
The system used to name the 30,000 or so fishes of the world is called "the binomial system of nomenclature". Through this system a fish is given a Latin scientific name, which is usually made of two parts: the genus and species, or three parts if a subspecies has been described. The genus name applies to a group of species displaying basic characteristics while the species name is based on a few characteristics that apply to one species which is distinct from all others.

Carcharhinus	limbatus
Genus	Species

For example, the genus Carcharhinus applies to many different sharks; the specific epithet for three of those sharks are Carcharhinus limbatus, C. falciformis, and C. leucas. Remember the first part the name is the genus (Carcharhinus) and the second part is the specific epithet (or species) (limbatus, falciformis, and leucas).