Types of Saltwater Fish

There are approximately 2,000 different species of saltwater fish that are imported and used in captivity. There are many other categories that have not been discovered. Saltwater fish, also known as marine fish, are found all over the World. These fish species are the most seen fish in aquariums. Saltwater fish comes in many different categories and many different species are bred in captivity.

On average, the measure of the fish in length ranges from 3.9-70.8 in (10-1800cm). They are pretty quick swimmers but it depends on the species. There are some species of saltwater fish that are poisonous, scorpionfish and boxfish are fish examples of poisonous saltwater times more poisonous than cyanide for humans.
Saltwater fish are known to drink water, unlike freshwater fish which are known to absorb water through their gills and skin. They need proper care and are harder to take care of than freshwater fishes.

There are about 24,000 known species of fish, about 15,000 species are saltwater.

Saltwater fish are vertebrates, some have vertebrae made of cartilage, while others have bony vertebrae, on the basis of these saltwater fish are classified into three types; jawless fish, cartilaginous fish, and bony fish.

Following are saltwater fish which are classified into different types-

Agnatha (jawless fish)

Agnatha is a jawless fish in the phylum Chordata jaws, jaws, fins and stomachs are absent in the jawless fish. Features of the jawless fish have two-chambered hearts, paired gill pouches, and pineal eyes.

Two types of jawless fish exist-

• Hagfish- Also called "slime eels" they are not eels. Skin is used to make wallets and handbags, any of about 70 Species of Marine vertebrates placed with the lampreys in the superclass agnatha. Hagfishes are scaleless, soft-skinned creatures with paired thick barbels on the end of the snout. Hagfishes are found in cold seawater, They live on soft bottoms, in burrows, and habitually lie buried except for the tip of the head. Their diet includes Marine invertebrates and dead or crippled fishes.
• Lampreys- Lampreys are an ancient extant lineage of jawless fish. There are about 43 Species of jawless vertebrates placed with hagfishes in the class agnatha. They have no jaws.

Chondrichthyes (cartilaginous fish)

Cartilaginous fishes have a skeleton made out of cartilage, that's why they are known as cartilaginous fish. There is a diverse group that comprises more than 700 species, Chondrichthyes are found throughout the world's oceans.

Osteichthyes (bony fish)

The scientific name of bony fish is Osteichthyes, you can easily find these fish by their scientific name. They include all bony fishes and are cold-blooded vertebrates that breathe through gills and use fins to swim. Bony fish play a major role in all Marine and freshwater ecosystems. Osteichthyes is a class of jawed fishes having a Bony endoskeleton. It is the largest class of vertebrates and includes a diverse group of saltwater and freshwater Bony fishes.