External Organ of Fish ( Anatomy of Fish )

Mouth: The mouth is used to consume food. Operculum: The operculum is the bony flap that protects the gills from harm. It opens and closes to allow water to pass over the gills. Pectoral Fin: The pectoral fin allows for abrupt changes in side-to-side direction and speed

1. EXTERNAL ORGANS OF FISH 7/20/2024 1

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3. Table of Contents 1 Mouth 2.Eye 3.Barbels 4.Operculum 5.Lateral line 6.Fins 7. Vent 7/20/2024 3

4. Mouth Generally, situated anteriorly in the head Location varies depends on species and feeding habit Location, type and size of the mouth is a good indicators of feeding habit and habitat of that fish Predatory fishes usually have a wide mouth, while herbivorous and omnivorous fishes have smaller mouth There are three general locations of the mouth of fish 1. Upturned or superior mouth: Lower jaw is longer than upper jaw Generally surface feeder 7/20/2024 4

5. 2. Terminal or Sub- Terminal mouth Upper jaw = lower jaw Column Feeder 3. Underslung or Inferior mouth Upper jaw is longer than lower jaw Bottom Feeder 7/20/2024 5

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7. b. Snout Portion of the head situated in front of the eyes. Has a pair of nostrils or nares on each side c. Nostrils Two nostrils on either side of the head (two pairs) They serve as olfactory organs that feels taste and smell No role in respiration 7/20/2024 7

8. Eyes Location: Lateral sides of the head Eye size and position vary depending on habitat and behaviors of the species Their lenses are spherical, a design that enables a fish to focus in water Fish do not have eye-lid ( except in some sharks) Fish do not sleep Fish eyes are not too good at judging distances but colors are perceived well 7/20/2024 8

9. Barbells Location : close to the mouth The barbells are used to screen the environment and increase awareness of its surrounding The barbells are equipped with taste buds and the fish use them when catching fish in dark and cloud water where the visibility is low 7/20/2024 9

10. Based on their origin, barbells are named as ` 1. Maxillary barbell: arise from the upper jaw 2. Mandibular barbell: Arise from lower jaw 3. Rostral barbell: Aries from the region of snout 4. Nasal barbell: Region of nostrils 7/20/2024 10

11. Operculum Covering and protecting the gills It opens and close to allow water to pass over the gills Elasmobranchs do not have an operculum but there are separate gill silts for each gill 7/20/2024 11

12. Lateral Line Sense organ Extending from head to tail Under the scales is a system of fluid-filled tube or canal and specialized cells which transmit vibrations to brain of the fish The lateral lime helps fish to detect movement and vibration in the surrounding water including predators and prey Some ichthyologists tell that the lateral line gives fishes the sense of “distance touch” It also feel the fish to feel pressure and temperature changes in water around it 7/20/2024 12

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14. Fins Major locomotory organs in fishes 7/20/2024 14

15. Vent External openings of digestive, urinary and reproductive tracts Location: posterior ventral side, just in front of the anal fin 7/20/2024 15

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