Fish Anatomy

Fish Anatomy

• Fish are vertebrates, possessing a backbone.
• Most fish have fins and scales (exceptions exist like catfish).
• Fish are cold-blooded and lay eggs.
• Fish are well-adapted to aquatic life.

External Anatomy

• Eyes: Used for sight, detecting colors, and short-distance vision for escaping predators and finding food.
• Nares: Similar to nostrils, used for smelling.
• Mouth: Used for consuming food.
• Operculum: A bony flap that protects the gills and allows water flow over them.
• Pectoral Fin: Enables side-to-side movement, changes in speed, and acts as a brake.
• Pelvic Fin: Stabilizes the fish during swimming and allows for up-and-down movement.
• Dorsal Fin: Helps maintain balance during swimming.
• Caudal Fin: Propels the fish through the water.
• Anal Fin: Aids in stabilizing the fish during swimming.
• Vent: Removes waste and extra water, and is a spawning outlet.
• Adipose Fin: A small, thick, fleshy fin located between the dorsal and caudal fins (may not be present in all fish).
• Scales: Protect the fish from injury.
• Barbels: Sensory organs, particularly on catfish and bullheads, used in detecting prey.

Internal Anatomy

• Gills: Feathery tissue structures that allow fish to breathe underwater, extracting oxygen from the water.
• Swim Bladder: A long, skinny organ that inflates/deflates with air, allowing fish to float at different levels in the water column.

Fish Senses

• Eyesight: Can see in two directions simultaneously (one eye focused on an object independently of the other eye).

• Hearing: Fish have internal ears with otoliths, which enable fish to sense sounds in the water.

Fish Senses (continued)

• Smell: Used to locate food and for migration.
• Taste: Fish can have some taste buds in areas apart from the mouth.
• Lateral Line: A system of fluid-filled canals that detect changes in water pressure, helping to locate predators and prey.