Fins are important appendages that help fish maintain position, move, steer and stop in water. They are composed of bony spines covered in skin and aid with mobility, stability and maneuverability. The main types of fins are paired (pectoral and pelvic) and unpaired (dorsal, caudal, anal). Each fin type has a distinct function in swimming, turning and balancing. Fins have evolved diverse shapes and forms to help fish survive in their environments.

1.  A fin is a thin component or
appendage attached to a larger
body or structure.
 most distinctive features
of a fish
 Compose of bony spine protruding from
the body with skin covering them and joining
them together, either in a webbed fashion,
as seen in most bony fish , or more similar
to a flipper, as seen in sharks.
 Fins are appendages used by
the fish to maintain its position,
move, steer and stop.
 Fins give fish mobility, stability,
and maneuverability.
•Help in protection form predator

4. Fins are composed of two groups
Paired and unpaired
Paired Fins
 Pectorals
 Pelvics orVentrals
Unpaired fins
 Dorsal
 Caudal or tail
 Anal

5.  Paired fins can be used as the main means of
propulsion or in combination with other swimming or
crawling forms.
 The pectoral and pelvic fins are also commonly used
as a means of
 Quickly stopping the fish,
 Controlling pitching (change of position from the
horizontal) and to
 Attract mates or startle other fish.
 Two well known examples of the use of the pectoral
fins for primary propulsion are:
 Labrids - the rowing type movement of the wrasse.
 Rajiform - the bird like swimming of the skates and
rays

6. 1:PECTORAL FINS
 On side of body , behind gill cavity
 In primitive fishes, the pectoral fins are found lower
on the body, nearer the ventral side.
 In some look like an arm-like extension.
 In other cases, the pectoral fins haveevolved to
look like wings for South American flying fish
 a pad for resting on the bottom in some catfish.

8. he pelvic fins are generally smaller than the
 The pelvic fins are located ventrally below and
behind the pectorals.
 Pelvic fins function in stabilizing , braking, move up
and down
 They are of little use for locomotion.
 Some have spines and rays on them.
 Other fish have modified pelvic fins in the form of a
sucker for holding on rocks.eg Gobies
 Some fish have even lost their pelvic fins
completely, especially those that spend their lives
scouring along the ocean floor.

11. 1:DORSAL FINS
 Dorsal fins are located on the back or on the top of the
fish
 Aid the fish in sharp turns or stops, and assist the fish in
rolling.
 Fish may have up to three distinct dorsal fins, known
as proximal, middle , and distal dorsal fins

12.  several fish have just two dorsal fins with the
middle and distal fins fused together.
 May be a fleshy ray, or quite large and
supported by spines.
 Dorsal fins have been modified in the
remoras into a sucking disc that allows them
to cling to sharks or other large fishes.
 In the anglerfish, the dorsal fin has been
modified into a fishing rod and lure.

13. Dorsal fin

14.  The type of Doral fins are:
 Single
 Split
 Pointed
 Trigger
 SpineTriangular
 Trailing

15.  The caudal fin is the tail tail located at the end of the
caudal peduncle.
 For fish identification, the type of Caudal fin is used to
distinguish one type from another.
Types of caudal fin
 Indented
 Round
 Square
 Forked
 Lunate
 Pointed
 Emarginate
 Heteroceral

17.  The anal fin is located on the ventral surface
behind the anus
 The anal fin is usually short, but some fish have
anals that stretch from near the chin, to the caudal
fin.
 Very few fish have more than
one anal fin(i.e., the cods),

18. •some do not have one at all (i.e., skates
and rays).
• In some species,the anal fin has modified
into an organ used in copulation called
gonopodium.

19.  Fishes such as catfish have another fleshy
lobe behind the dorsal fin, called an adipose
(fat) fin
 Its function has remained a mystery
 Additional released in 2011 has suggested
that the fin may be vital for the detection of
and response to stimuli such as touch, sound
and changes in pressure

21.  Finlets are small fins located between the
dorsal fin and the tail of the fish
 anal fins and the tail of the fish.
 These finlets are found on fast swimming fish
like tuna, and is said to aid in the speed of the
fish, by cutting through the water.