Characteristics: -
i) Members of this class also called fishes.
ii) Their body has three parts, i.e. head, trunk, tail.
iii) Body of fish is flexible.
iv) They can swim in water with the help of fins.
v) Their bodies are covered with scales, which remains most by special
secretion of body.
vi) They have gills on both sides of head, which help it to respire.
vii) Mouth has teeth, which are used for grasping instead of grinding.
viii) Air bladder is present in some fishes, which are used for buoyancy.
ix) Fishes are cold-blooded animals. They cannot maintain their body
temperature as per environment.
x) Some fishes have body skeleton.
xi) Some fishes live singly. Other live in groups called school.
xii) In fishes pupil size is large compared to other vertebrates, which permits
more light. Fishes have no eyelids.
Example (Rahu): -
i) It is found in fresh water.
ii) It is herbivorous.
iii) Its body length is 2-3 feet.
iv) Mouth is present on the ventral side.
v) Teeth are absent in jaws.
vi) A single gill opening is present called operculum.
vii) Its body is covered with scales.
viii) Scales are absent in the head region.