Pisces (Fishes)- Characteristics, Classification, Examples

Pisces are marine animal that are truly jawed vertebrates.–> Definition

In this article we have covered everything related to Pisces, from characteristics to examples. Let’s dive right into the characteristics features of Pisces.

General Characteristics Features of Pisces

  1. Aquatic, either fresh water or marine, cold blooded vertebrates.
  2. The skin is covered with scales, dermal denticles or bony plates.
  3. Body usually streamlined, some are elongated, some are compresses.
  4. Paired and unpaired fins with supporting fin rays.
  5. Tail is muscular organ used for locomotion.
  6. Nostrils are paired, do not open into pharynx, except in dipnoids.
  7. Lateral line system is well-developed.
  8. Venous heart with one auricle and one ventricle.
  9. Ten pair of cranial nerves.
  10. Internal ear is present, with three semi-circular canals.
  11. Kidney is mesonephric.
  12. Gonads and true gonoducts are present.
  13. Sexes are separate.
  14. Amnion is absent.
  15. Examples of Pisces (Fishes) are: String Ray, Electric Ray, Saw Fish, Dog Fish, Sucker fish, Sea Horse etc.

Classification of Pisces (Fishes)

Super class Pisces is divided into following classes:

Class 1: Placodermi-Extinct

Example: Dinichthyes

Class 2: Chondrichthyes

  1. Endoskeleton is cartilaginous.
  2. Skin with placoid scales.
  3. Pelvic fins bear claspers in male. Tail is heterocercal.
  4. Gill slits 5-7 pairs, not covered with operculum.
  5. Notochord is persistent. Vertebrae complete.
  6. Stomach J-shaped and intestine with spiral valve.
  7. Heart two chambered, one auricle and one ventricle. Sinus venous and conus is present.
  8. Kidney opisthonephric.
  9. Brain with large cerebellum and 10 pairs of cranial nerves.
  10. Fertilization internal. Development is direct, oviparous and ovoviviparous.

Class 3: Osteichthyes

  1. Skin with mucous glands, ganoid, cycloid or ctenoid scales.
  2. Endoskeleton mainly body. Notochord replaced by vertebral column.
  3. Gills four pairs covered with operculum.
  4. Swim bladder is usually present.
  5. Pelvic girdles are small and simple, claspers absent.
  6. Heart two-chambered, one auricle and one ventricle. Sinus venous and conus are present.
  7. Cold blooded.
  8. Cloaca absent. Anus present.
  9. Adult kidneys are mesonephric.
  10. Brain with large optic lobes and cerebellum, 10 pairs of cranial nerves and lateral line system.
  11. Mostly oviparous.

Some Examples of Pisces

SCOLIODON (Dog Fish)

Classification of Scoliodon

PhylumChordata
SubphylumVertebrata (Craniata)
DivisionGnathostomata
Super classPisces
ClassChondrichthyes
SubclassSelachii
Super OrderPleurotremata
OrderLeminiformes
GenusScoliodon

Distribution

It is found in Indian ocean, Zanzibar, Sri Lanka to Malaysia Archipelago, East Indies, Philippine Islands, Mexico to Panama, Cuba, West Indies and South Africa.

Habits and Habitat

  • It is a common shark found in the open sea all along the Indian coast.
  • It is an active swimmer, carnivorous, predaceous and is able to scent blood from long distance and attacks enemies with its powerful jaws.

Characteristics of Scoliodon

  1. Commonly known as Dog fish.
  2. The body elongated and spindle like.
  3. The body is divisible into head, trunk and tail.
  4. Paired pectoral and pelvic fins, and median unpaired dorsal, ventral and caudal fins are present.
  5. Five pairs of gill slits are present.
  6. Mouth is ventral and crescentic, armed with teeth.
  7. Lateral fin system well developed.
  8. Heterocercal tail is present.
  9. The eyes are large and circular.
  10. The external nostrils are large and ventral.
  11. Male has copulatory organs known as claspers.
  12. The cloacal aperture lies between pelvic fins.
  13. It is dangerous to swimmer.
  14. It has a food value.
Scoliodon (Dog fish) Diagram
Scoliodon (Dog fish) Diagram

PRISTIS (Saw Fish)

Classification of Pristis

PhylumChordata
SubphylumVertebrata (Craniata)
DivisionGnathostomata
Super classPisces
ClassChondrichthyes
SubclassSelachii
Super OrderHypotremata
OrderRajiformes
GenusPristis

Distribution

It is found in Seas of tropical and temperate regions. It is very common in seas from India to Malaysian Archipelago. Sometimes it enters Mahanadi of Odisha state present in India.

Habits and Habitat

  • Marine and active swimmer.
  • Carnivorous and predaceous, feeds on small fishes which they slash with their saw.

Characteristics of Pristis

  1. It is commonly known as Saw fish.
  2. The body is elongated, compresses and divided into head, trunk and tail.
  3. It grows up to a length of 10 to 20 feet.
  4. Head and skull are prolonged into rostrum, the lateral margins of which contain a series of strong tooth-like denticles giving it the appearance of saw.
  5. No rostral tentacles present.
  6. Teeth in jaws are minute.
  7. A pair of eyes and spiracles are present on dorsal surface of head. Gill slits are present.
  8. Dorsal fins are large, the first dorsal fins is opposite to the pelvic fin.
  9. Tail is heterocercal.
  10. Predaceous, feeds upon small fishes and flesh of marine animals.
  11. Its liver oil is rich in vitamins and has nutritional value.
  12. Skin is used for making scale boards.
Pristis (Saw Fish) Diagram
Pristis (Saw Fish) Diagram

TORPEDO (Electic Ray)

Classification of Torpedo

PhylumChordata
SubphylumVertebrata (Craniata)
DivisionGnathostomata
Super classPisces
ClassChondrichthyes
SubclassSelachii
Super OrderHypediformes
OrderTorpediformes
GenusTorpedo

Distribution

World wide disrtibution, found in Mediterranean, Atlantic and Indian Oceans, Red sea, Pacific oceans, Tasmania, China, Japan, South Africa, Australia, North and South America.

Habits and Habitat

  • It is a marine fish found at a depth of 40-50 fathoms on the sea bottom.
  • It is carnivorous.

Characteristics of Torpedo

  1. These are marine and commonly known as Electric Ray.
  2. The body is dorsoventrally flattened and disc-shaped or sub-circular.
  3. The semi-circular anterior margin of the disc is supported in the center by a branched prenasal rostrum and laterally by the branched pre-orbital cartilages.
  4. Pectoral fins joined with head.
  5. Skin is smooth without scale.
  6. Mouth is transverse and ventral in position.
  7. Quadrangular naso-frontal lobe is present.
  8. A pair of eyes and the spiracles are present dorsally on the head.
  9. A pair of electric organs on either side of the head, between the pectoral fin and the head. Electric organs consist of muscle fibers and connective tissues arranged in columns of block. A special nerve supply is present.
Torpedo (Electric Ray) Diagram
Torpedo (Electric Ray) Diagram

TRYGON (String Ray)

Classification of Trygon

PhylumChordata
SubphylumVertebrata (Craniata)
DivisionGnathostomata
Super classPisces
ClassChondrichthyes
SubclassSelachii
Super OrderHypotremata
OrderRajiformes
GenusTrygon

Distribution

It is distributed in seas and estuaries in India, particularly in the Hooghly rivers at Calcutta and Bengal.

Habits and Habitat

  • It is found usually lying quietly on the sea bottom.
  • It is carnivorous and feeds on small fishes, molluscs etc.

Characteristics of Trygon

  1. Commonly known as the String Ray.
  2. Body is flat, disc-like and broader than long.
  3. Pectoral fins are united with the head.
  4. Mouth and 5 pairs of gill slits are ventral in position.
  5. A rectangular naso-frontal flap present in front of mouth.
  6. The spiracles are present behind the eyes on dorsal side.
  7. Tail is long and slender. The tail is whip-like, terminating in small caudal fin and armed with a sharp serrated poisonous spines or string. String is painful to man.
  8. The string is the modified fin.
  9. Claspers are present near the pelvic fins in male.
  10. Viviparous, carnivorous, feeds upon small fishes.
  11. It is used by people as food and its liver yields oil.
  12. It shows adaptive coloration to conceal itself from the enemies.
Trygon (String Ray) Diagram
Trygon (A) Male (B) Female

ECHENEIS (Sucker Fish)

Classification of Echeneis

PhylumChordata
SubphylumVertebrata (Craniata)
DivisionGnathostomata
Super classPisces
ClassTeleostomi
SubclassActinopterygii
OrderEcheneiformes
GenusEcheneis

Distribution

It is distributed over the tropical and warm seas but specially found on the south coast of England.

Habits and Habitat

  • Marine and carnivorous fish feeding on small fishes.
  • It attaches itself to other fishes, boats, marine turtles etc. by means of its adhesive disc or sucker.

Characteristics of Echeneis

  1. It is commonly known as Sucker Fish.
  2. The body is elongated, fusiform and covered with small scales.
  3. Head is dorsoventrally compressed and has a dorsal adhesive sucker.
  4. Generally found attached to fishes, marine turtles and other sea animals.
  5. Eyes are lateral in position.
  6. Mouth cleft is wide and deep.
  7. First dorsal fin is modified into an adhesive disc.
  8. Adhesive disc or sucker is flat, composed of many long plates called lamellae. It is an effective organ for attachment.
  9. Second dorsal fin and anal fins are elongated without spines and opposite to each other.
  10. Tail is homocercal.
  11. Air bladder is present.
  12. Eyes and nostrils are present.
  13. It is employed to catch the turtle on the coast of Africa.
Echeneis (Sucker Fish) Diagram
Echeneis (Sucker Fish) – (A) Dorsal View (B) Fish in Lateral View

HIPPOCAMPUS (Sea Horse)

Classification of Hippocampus

PhylumChordata
SubphylumVertebrata (Craniata)
DivisionGnathostomata
Super classPisces
ClassTeleostomi
SubclassActinopterygii
OrderSyngnathiformes
GenusHippocampus

Distribution

It has worldwide distribution, commonly found in Indian, Malaysia, China, Japan and Archipelago.

Habits and Habitat

  • It is a marine fish, feeds on micro-organsism.
  • It swims in vertical position by dorsal fin, holding a weed with its tail.

Characteristics of Hippocampus

  1. Hippocampus is commonly known as Sea Horse.
  2. The body is more or less elongated having an exoskeleton of rings.
  3. Head changes into a tubular snout resembling that of a horse giving it a common name of Sea Horse.
  4. The mouth is situated at the extremity of the snout.
  5. The trunk is compressed and covered by body rings or scutes.
  6. The dorsal fin is small.
  7. Pelvic, anal and caudal fins are absent.
  8. The tail is prehensile and used as a brake when the sea horse swims vertically upwards.
  9. The operculum is fused with the body wall leaving a small pore.
  10. The male carries the eggs on the ventral surface in the brood pouch present on the abdomen, until they hatch.
  11. It feeds on microorganisms by the siphoning action of the snout.
  12. It conceals itself among seaweeds and escapes the observation of the enemies.
Hippocampus (Sea horse) Diagram - Male and Female
Hippocampus (Sea horse) Diagram – (A) Male and (B) Female

ANABAS (Climbing Perch)

Classification of Anabas

PhylumChordata
SubphylumVertebrata (Craniata)
DivisionGnathostomata
Super classPisces
ClassTeleostomi
SubclassActinopterygii
OrderPerciformes
GenusAnabas

Distribution

It is found in fresh waters in of India, Sri Lanka, Myanmar etc.

Characteristics of Anabas

  1. It is commonly known as Climbing Perch.
  2. Body is covered with ctenoid scales.
  3. Mouth is terminal and jaws bear filiform teeth.
  4. Lateral line is broken or discontinuous.
  5. A backwardly directed small spine is present on the operculum.
  6. Accessory respiratory organs are covered by a vascular membrane and present near the lamellated gills.
  7. It feeds on earthworms and molluscs.
  8. It is used as food by man.
Anabas (Climbing perch) Diagram
Anabas (Climbing perch) Diagram

SYNAPTURA (Flat Fish)

Classification of Synaptura

PhylumChordata
SubphylumVertebrata (Craniata)
DivisionGnathostomata
Super classPisces
ClassTeleostomi
SubclassActinopterygii
OrderPleuronectiformes
GenusSynaptura

Distribution

Synaptura is found in the area of India to Malaysia Archipelago, Andaman Straits, rivers of Odisha and Ganges delta.

Characteristics of Synaptura

  1. Synaptura is commonly known as Flat fish.
  2. Body is thick, laterally compressed and flat, sole-like.
  3. Scales covering the body are usually imbricate.
  4. Both the eyes and mouth are on upper side of the body and lateral in position due to the twisting of neurocranium.
  5. Head is asymmetrical.
  6. Dorsal and anal fins are long; without spines and confluent with the caudal fins.
  7. Air bladder is absent, caudal fin well-developed.
  8. Four gill slits are present. Pseudobranchialare are present.
  9. Body is flat due to bottom dwelling habit.
  10. It is relished as food.
Synaptura (Flat Fish) Diagram
Synaptura (Flat Fish)

CATLA

Classification of Catla

PhylumChordata
SubphylumVertebrata (Craniata)
DivisionGnathostomata
Super classPisces
ClassTeleostomi
SubclassActinopterygii
OrderCypriniformes
GenusCatla

Distribution

It is found all over India, but less in the South, in river Krishna.

Habits and Habitat

  • It is found in fresh water rivers, lakes etc.

Characteristics of Catla

  1. Catla is the largest Indian carp and is commonly known as Katla in Hindi (Language spoken in India).
  2. Body is elongated, broad and stout, covered by cycloid scales and measuring more than three feet in length.
  3. Color blackish-grey above and silvery on the sides.
  4. Scales are deep greyish or copper colored on dorsal surface and white on ventral surface.
  5. Dorsal side is more convex than ventral.
  6. Head is large with rounded eyes, mouth is terminal and wide with lips.
  7. Dorsal fin is large. Caudal fins are bilobed.
  8. Air bladder is large and divided into anterior and posterior chambers.
  9. Highly relished as food and has much nutritional value.
Catla Fish Diagram
Catla Fish Diagram

BARBUS

Classification of Barbus

PhylumChordata
SubphylumVertebrata (Craniata)
DivisionGnathostomata
Super classPisces
ClassTeleostomi
SubclassActinopterygii
OrderCypriniformes
GenusBarbus

Distribution

It is a very common fish found in rivers, ponds and lakes of India and Myanmar.

Habits and Habitat

  • Freshwater forms.

Characteristics of Barbus

  1. Commonly known as Mehasheer in Hindi (Language of India) or Minnows.
  2. The body is perfectly streamlined to swim against water current.
  3. Snout is pointed, body is spindle shaped and tail is long.
  4. Cycloid scales are hexagonal and very large.
  5. Head is without scales and bears a pairs of large eyes and small barbels.
  6. The pectoral fins are small without spines.
  7. The dorsal fin is large and the pelvic fins are backwardly placed.
  8. Barbus grows up of to a length of 1 meter.
  9. the back is dark green in color and the lower surface is golden.
  10. The fish is used as food.
Barbus Diagram
Barbus Diagram

Labeo

Classification of Labeo

PhylumChordata
SubphylumVertebrata (Craniata)
DivisionGnathostomata
Super classPisces
ClassTeleostomi
SubclassActinopterygii
OrderCypriniformes
GenusLabeo

Distribution

It is very commonly found in freshwaters of India, Myanmar, Tropical Africa and Syria.

Habits and Habitat

  • This Indian carp is abundantly found in fresh-water ponds and rivers.
  • Herbivorous and bottom feeder.

Characteristics of Labeo

  1. Labeo is the most popular Indian carp and is known as Rohu in Hindi (language spoken by Indian) or carp.
  2. The body is elongated with a moderately rounded abdomen measuring up to three feet in length.
  3. The colour is brownish-grey to black above.
  4. Scales are cycloid and orange to reddish in the centre.
  5. Head is prominent with a blunt snout.
  6. The mouth is transverse and semioval.
  7. Lips thick covering jaws, one or both having inferior transverse fold.
  8. A pair of filamentous barbels arise from the upper lip.
  9. The lateral line is distinct.
  10. The air bladder is large and divided into an anterior and posterior part.
  11. It is used as food and has nutritional value.
  12. Pectoral, pelvic, dorsal, ventral and caudal fins are present.
Labeo Fish Diagram
Labeo Fish Diagram

CLARIAS (Cat Fish)

Classification of Clarias

PhylumChordata
SubphylumVertebrata (Craniata)
DivisionGnathostomata
Super classPisces
ClassTeleostomi
SubclassActinopterygii
OrderCypriniformes
Sub orderSiluroidea
GenusClarius

Distribution

It is commonly distributed in India, Sri Lanka, Myanmar and Malaysia, also Archipelago.

Habits and Habitat

  • It is found in brackish water. It takes clams, insects larvae and crustaceans as food.
  • It generally lives in muddy water.

Characteristics of Clarius

  1. Commonly known as Cat fish.
  2. Dorsal fins extends all along the body.
  3. Pectoral fin is inserted very low.
  4. Anal fin is not confluent with caudal.
  5. Head with four pair of sensory barbels.
  6. Body is covered by naked skin (scale-less).
  7. Air bladder is present.
  8. Eyes reduced and spiracles absent.
  9. Tail is compresses, diphycercal and having rounded caudal fin.
  10. It is highly nourishing and esteemed as food.
  11. Accessary respiratory organs are branched tree-like, especially designed to take in oxygen from the air.
Clarias (Cat Fish) Diagram
Clarias (Cat Fish) Diagram

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