The three-spined stickleback fish exhibits distinct breeding behaviors between males and females. Males will isolate themselves from schools at the start of breeding season and establish territories, defending them aggressively from other males. Within their territory, males will undergo color changes and build nests out of plant materials. They then perform zigzag dances to attract females and fertilize the eggs females lay in the nest. For around two weeks, males will fan the nests to provide oxygen for developing eggs and guard the hatched young.

1. Breeding
Behaviour
Of Three
Spined
Stickleback Fish

2.  Sticklebacks are a good example
of male dominating and nesting
behaviour.Sticklebacks normally
breed between late March and
early August.During these months,
there is plenty of food around for
the young fish.
 Usually,sticklebacks live in
SCHOOLS. But at the beginning of
breeding season,the males isolate
themselves from school.

3.  TERRITORY SELECTION
 Breeding process of three spined sticklebacks starts with “Territory
Selection”.The male select a safe place where he can build a nest,
fertilize eggs and can take care of infants without any disturbance.
 If another fish,and particularly another male,enters the territory,it
is attacked.Again,fighting is rarer than threat.The stickleback dart
towards the opponent with raised spines and open mouth to
bite,but it actually doesn’t bite.The ownwer then make some jerky
movements to drive away the opponent. This is called “BOUNDARY
FIGHT”.

5.  COLOUR CHANGE
In the early spring.the male stickle backs undergoes quite a
dramatic transformation.His throat and belly becomes red-
orange,his eyes turns bright blue and silvery scales appears on
his back.

6. NEST BUILDING
 Attired in his bright colour,the male then sets about building a mound-
shaped nest in a hollow bottom,using bits of water plants ,bound by
sticky glue secreted from his kidneys.He use his mouth to glue the bits
of plants together.
 After resulting a green cluster,the male then bores a tunnel by wriggling
itself right through th nest.

8.  When it finished nest building,it color started becoming
more intese red.All the black cells are vanished and
guanine bluish crystals of underlying sking are exposed
to turn into shiny whitish blue.Showing this shining
appearance ,the male attracts the females

9. Female stickleback fish

10. ZIGZAG DANCE
 In the meantime,the mature females have developed a brilliant
silvery gloss,and their bodies are heavily swollen by the bulky eggs
which have developed in their ovaries
 They cruise about in schools.Each male,if ready to receive a female
,reacts to them by performing a curious dance all around them,known as
“Zigzag Dance”.In this courtship dance,the male first tuns opposite to
female and then abruptly turns toward them with mouth open as it is
going to hit the female.But it actually does not do.Sometime this activity
frightens the female.But a single may be enough mature to spawn.

13. FERTILIZATION
 Then the male immediately hurried towards the nest.The female
follows it.
 The female penetrate into the narrow opening of the nest with a
strong beat of her tail and slips in.She remain in the nest,her head
protruding from one end ,the tail from the other.After some time she
begins to lift her tail and spawns.Yhis done,she quietly pushes through
the nest,while the male enters and fertilize the eggs.

16. FANNING
 After fertilization is completed,the male chases the female and
restore the roof which has been lifted.
 The male may court two,three or even more females and collect
several clutches of eggs.Then it shows parental behaviour.This is done
by a special movement,called “Fanning”.
 The male sends water currents down on the nest to supply oxyzen for
development of eggs.In the beginning,the fanning process may be
given 200 seconds in each half an hour.This gradually increase the
next eight days and may take three quarters of it's time.

17.  The male stops fanning after 7 or 8 days,when the young hatch and
the male guards the young carefully.
 After 2 weeks,the young develop more initiative and move further
from the nest and the male still guards them.Gradually he losses
interest as well as nuptial colour.
 After some week,The male leaves the youngs and join his
school,while young keep to companions of their own.

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