Fish Anatomy, Physiology and Health

The anatomy of a fish

Fins

• Made of stiff rays covered by skin

• Some are bony and stiff

• Cichild fish have one dorsal, but it has two names, a spiny dorsal and a soft dorsal

• The number of rays in a fin are used for species ID and classification

Skin

• Epidermis and Dermis– Consistently shed and replaced with new

epithelial cells– Interspaced between epithelial cells are slime

cells which produce Mucoid, the slime that forms the protective covering called the slime coat

ACTIVITY

• Go look at the fish scales under the microscope and draw what you see.

Pigment cells

• Colors are produced by cells in the dermis

• Fish can change color during mating, as a survival tactic and during feeding times

• This is caused when melanin grains are moved within each pigment cell, when dispersed they absorb more light and the fish darkens. When they are tightened, the fish goes pale.

Gills

• Respiration occurs here

• Composed of a delicate system of blood vessels, which allows the gaseous exchange to take place.

Lateral Line

• Connects scales to sensory cells and nerve fibers

• Runs in a semi-line from gills to the tail fin, easily noticed as a darker line running along the side of the fish.

• Very important sensory organ

Physiology of Fish

• The function of body systems• 9 body systems are found in fish:

– Circulatory system– Digestive system– Excretory system– Muscular system– Nervous system– Reproductive system– Respiratory system– Sensory system– Skeletal system

Circulatory system

• Distributes blood throughout the body

• Consists of : heart, veins, arteries

• Fish have a 2 chambered heart

Digestive System

• Converts food to use for maintenance, growth and reproduction

• Includes mouth, esophagus, stomach, intestines, liver, anus and other associated organs.

• Systems vary according to the animals eating habits.

Excretory System

• Kidneys filter waste from the blood

• Through usage of energy, fish are able to break down the nitrates and ammonia to a more usable source of urea.

Muscular system

• Provides external and internal movement

Nervous System

• Conveys sensory impulses between the brain and spinal cord, or other parts of the body as well.

• Consists of brain, spinal cord, sensory receptors and nerve fibers

Reproductive System

• Some fish are eggs layers, while others are live bearers.

• When the sperm and egg unite a zygote is created and after a period of incubation the zygote becomes an organism

Respiratory System

• Gills are the respiratory organs of fish, shellfish and crustaceans.

• Water taken in by the gills is where oxygen is removed by diffusion in the blood

Sensory System

• Includes 5 senses: sight, touch, taste, smell and hearing

• Fish also have the lateral line which is very important in detecting minute electrical currents in the water.

Skeletal System

• Rigid framework which gives the body shape and protects the organs.

• Fish possess an internal skeleton while shrimp, oysters and crawfish have an external skeleton

Fish Health, Pests and Disease

• When selecting fish for your aquarium, look for fish that:– Have a healthy appearance– Are active– Eat well – Have no scars, spots or open wounds

Common Fish Diseases

• Ick

• Bacterial Fin Rot

• Gill and Skin Flukes

• Dropsy

• Ammonia Poisoning

• Nitrite Poisoning

Activity

• Choosing one of the fish diseases listed on the previous slide, you are going to research the symptoms, causes and treatments.

• You will need to make a poster with at least 2 pictures of the disease affecting a fish, as well as list the symptoms, causes and treatments. BE CREATIVE!!!