TYPES OF CAUDAL FINS

The fins are usually the most distinctive anatomical characteristics of a fish. They are composed of bone spines or rays that protrude from the body with the skin that covers them and joins them, either in a webbed form, as seen in most bonefish, or similar to a fin, as seen in sharks. In addition to the tail or caudal fin, the fins of the fish have no direct connection to the spine and are only supported by the muscles. Its main function is to help the fish to swim.

The fins located in different places of the fish serve different purposes, such as moving forward, turning, maintaining a vertical position or stopping. Most fish use fins when they swim, flying fish use pectoral fins to slide and frogfish use them to crawl. The fins can also be used for other purposes; male sharks and mosquito fish use a modified fin to release sperm, fox sharks use their caudal fin to stun prey, reef stonefish have spines on their dorsal fins that inject venom, monkfish use the first spine of its dorsal fin like a fishing rod to attract prey, and triggerfish prevent predators by squeezing into the cracks of corals and using thorns on their fins to lock in place.

 CAUDAL FINS

The caudal fin, or tail, of a fish, is the only fin that connects to the spine. It is the main means of locomotion for most fish. Unlike many marine mammals with tails that use an upward and downward movement, fish generally use a thrust from side to side of their caudal fin for propulsion. The shape of the caudal fin can be indicative of the movement style of a fish. For example, fish that swim very fast, such as tunas, have semilunar caudal fins for more efficient swimming, while lurking predators such as grouper have a strong and wide tail base, the caudal peduncle, for acceleration faster.

Caudal fin is well developed in most of the fishes because it is an important contributor to forward propulsion during swimming. Three main types of the caudal fin are found i.e. Diphycercal, Hetrocercal, Homoceracal.

TYPES OF CAUDAL FIN

The types of the Caudal fins  are as follows

Diphycercal caudal fin

Heterocercal caudal fin

Homocercal caudal fin

 

Diphycercal caudal fin

Most primitive kind of tails or caudal fin was not exhibited by living fishes. The vertebral column extends straight back to the tip of the tail and dividing the fin into two equal lobes. The upper lobes are known as Epidermal lobe and the lowermost lobe is known as the Hypodermal lobe. Diphycercal caudal fin occurs in modern cyclostomes, primitive sharks, lungfishes.

Heterocercal caudal fin

HETEROCERCAL CAUDAL FIN

It is the intermediate type, in which vertebral column bends upwards and reaches up to the tip of the more prominent dorsal lobed thus making caudal fin strongly asymmetrical. It is typical of modern Elasmobranchs.  Heterocercal  caudal fins are characteristics of bottom feeders, with ventral mouth and without swimbladder

 Homocercal caudal fin

HOMOCERCAL CAUDAL FIN

This is the advance and most common type characteristics of the majority of higher bony fishes.

It is externally symmetrical but internally it is asymmetrical the vertebral column is short and asymmetrical. The homocercal caudal fin is the characteristics of fishes with a terminal mouth.