External Anatomy of fish

External Anatomy of fish

1. Body Shape

   • fusiform
   • laterally compressed
   • dorsal compressed
   • depends on lifestyle

2. Skin

   • Two layers
   • Epithelial
   • Dermis
   • Epithelium contains glandular cells
     • secrete slime coat

3. Scales

   • Calcified plates embedded in skin
     • Protects from injury
   • If lost the will grow back

4. Fins

   • flexible
   • supported by visible spines
   • Stiff rays covered by skin
   • Functions
     • Dorsal
       • Stability
     • Caudal
       • main propelling fins
     • Anal
       • Stability
     • Pectoral fin
       • Paired
         • Ventral fin
           • stability
       • Locomotion
         • side movement
     • Pelvic fins
       • paired
         • Adipose
           • stability
       • stability

5. Mouth

   • Takes in food
   • Takes in water to pass over gills

6. Operculum

   • Gill plate
   • Modified bone
   • Protects the delicate gills below
   • Sharks and rays dont have one

7. Barbels

   • Whiskers
   • Dectect food
   • Touch and taste receptors
     • Locate food

8. Olfactory Pit

   • Nares or nostral
   • organ of smell
   • locates food
   • detect a mate

9. Lateral Line

   • visible dark thin line
   • row of modified scales with pores
     • connected to canals of sensory cells and nerve fibres
   • detects vibration
   • detects eletrical currents
   • identify surrounding

10. eyes

    • similar to mammalian except lens
    • not important sense
      • lack of light in water

11. Other senses

    • Hearing
      • present, not understood
    • Taste
      • located in the mouth
      • skin covering head
      • body fins
      • barbels
      • lips
    • tactile sense
      • barbels as extensions of body

12. Vent

    • Conatins
      • anus
      • urogenital opening
        • caudal to the anus

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