1. Fish Morphology
Great diversity
exists among
fishes body
types and in
adaptations
they have that
help them
survive in their
environment

2. Body Shape - Fusiform
• Streamlined, torpedo-
shaped
• Fast open water swimmers
• Predators
• Move tail side to side
• Ex: Tuna, Swordfish, Shark,
Striped Bass, Salmon

3. Fusiform
Elfin Cove, AlaskaElfin Cove, Alaska
Orient Point, New YorkOrient Point, New York

4. Body Shape - Compressiform
• Compressed from side to
side
• Quick bursts of speed over
short distances
• Live among plants, move
among narrow spaces
• Move tail side to side
• Ex: Moonfish, Butterflyfish
Front
view

5. Body Shape - Depressiform
• Flattened top to bottom
• Live on the bottom
• Predators or scavengers
• Flap fins up and down,
swim like a bird
• Ex: Halibut, Flounder,
Skates, Rays
Front
view

6. Elfin Cove, AlaskaElfin Cove, Alaska Montauk, New YorkMontauk, New York
Check out tail shape Check out tail shape
Depressiform

7. Body Shape – Filiform (Attenuated)
• Elongated shape
• Slow
• Live soft mud, sand, or
under rocks
• Slither like a snake
• Ex: Eels, Sand Lance
Side
view

8. Caudal Fin Shape
• Caudal Fin = Tail
• Homocercal = symmetrical
• Heterocercal = asymmetrical

9. Tail Shape – Homocercal-Rounded
• Large amount of surface
area allows sharp turns,
quick starts for predator
avoidance
• Creates drag, fish tires
easily
• Ex: Northern Puffer,
Clownfish

10. Tail Shape – Homocercal-Truncate
• Allows short bursts of
speed to escape predators
or constant slow
swimming
• Less drag than rounded
• Bottom dwelling fish
• Ex: Killifish, Flounder,
Halibut (see slide 6)

11. Tail Shape – Homocercal-Forked
• Allows constant swimming
over long distances,
reduces drag
• Open water swimmers
• Don’t need speed for
protection or to catch
food
• Ex: Many schooling fish,
Menhaden, Striped Bass,
Porgies

12. Huntington, New
York
Huntington, New
York
Smithtown, New YorkSmithtown, New York
Homocercal-
Forked

13. Tail Shape – Homocercal- Lunate
• Half-moon shaped
• Fast moving oceanic
swimmers
• Less drag, great acceleration,
reduced maneuverability
• Ex: Tuna, Swordfish

14. Tail Shape – Heterocercal
• Medium speed
• Asymmetrical – top longer
than bottom
• No air bladder, so tail provides
lift
• Reduced maneuverability
• Ex: Many sharks