Difference Between Bony Fish and Cartilaginous Fish

A hundred years of evolution have produced two superficially identical species of fish while their skeletons are the most obvious difference between species.

Bony fish, as their name implies, have a skeleton made entirely of bone, while bony fish have a skeleton made entirely of bone. There are 20,000 different fish around the world.

Difference Between Bony Fish and Cartilaginous Fish

Pisces is the hyperclass of the bandit class. The explanation for this is that fish make up more than half of the chordate. Fish in this category belong to the group Osteichthyes or Chondrichthyes (bony fish or fish with bone).

What is Bony Fish?

This includes mostly bony fish. This type of fish is found in fresh water as well as in sea water. These fish have internal skeletons made of bone and are therefore called bony fish. Their exoskeleton is composed of scales, which can be discic or ctenoid or ganoid. Placoid scales are absent.

These fish species breathe with 4 pairs of gills. The gills are covered by an operculum on each side of the body. Their lips are generally terminal or penultimate, and the teeth are visible in the jaw. The chin-suspension has its own style.

Among them, the respiratory components are mainly assisted by the airways. Lungfish breathe through air sacs. In other fish, these air sacs are fluid, which help stabilize the body and provide buoyancy. With an internal roller valve, the vortex does not exist in them.

The cloaca is absent, the anus is present instead of the cloacal foramen, and there is no ampulla of Lorenzini. Their skull is triangular and their tail is generally homocerca but can sometimes be bificerca. Fish reproduce but can give birth or give birth.

What is Cartilaginous Fish?

Characteristics of Chondrichthyus are briefly discussed below. This species consists of cartilaginous fish and is marine in nature. Their endoskeleton is cartilaginous and the notochord lasts for life.

The exoskeletons on the dermis are formed by placoid scales and these scales resemble tooth fragments and originate from the epidermis and their teeth are inverted placoid pulp, receding along the way.

These fish have 5 – 7 pairs of hairs that open directly from the body through the slits of the egg. The operculum is generally absent in these fishes. In these cases, the mouth is located on the surface of the ventral head.

There are jaws and teeth. The jaw lines are Hyalostilic. Their jaws are powerful beasts of a portal nature. They have neither an air bladder nor lungs, as they must constantly swim to avoid drowning.

They also have this sewer hole as well as what appears to be a spiral valve or scroll valve to increase the length of the gut. Their livers are essentially bilateral. These fish have a special structure at the back of the head called the “Ampullae de Lorenzini” which functions as a heat sink.

The genitals of these organisms open into a sewer opening. The spawning system is internal because male fish have “claspers” like connective tissue that form on the inner edges of the pelvic fins. Most of them are conversational in nature.

Difference Between Bony Fish and Cartilaginous Fish

Cartilaginous Fish

Bony Fish

Biological Classification

Cartilaginous fishes fall under the class Chondrichthyes All bony fish fall under the superclass Osteichthyes


Primarily composed of cartilage Primarily composed of bone


Present Absent


Heterocercal in nature Homocercal in nature


Members primarily inhabit marine ecosystems. However, some exceptions are present Members inhabit both marine and freshwater ecosystems

Mode of Fertilization

Internal (exceptions are present) External

Swim Bladder

Absent. Buoyancy is maintained with oil stored in livers. Present (except for some bony fishes that dwell in the deep).


Great white sharks, whale sharks and every other species of sharks Sunfish, Tuna, Herring, Trouts etc

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