Environmental Resources
Unit C
Animal Wildlife Management
Problem Area 3
Fish Management
Diagnosing Fish Diseases
Lesson 7
Diagnosing Fish Diseases
• How many of you have had a cold or the
flu lately?
• What was some of the symptoms you
had?
• How did you treat this illness?
Terms
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Abscess
Bacterial disease
Bathing
Chemical disease
Cyst
Dipping
Environmental
disease
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Feed additive
Fungal disease
Hosts
Indefinite treatment
Infectious disease
Lesion
Non-infectious
disease
Terms
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•
•
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Nutritional disease
Parasites
Parasitic disease
Physiological
disorders
• Prevention
• Quarantine
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Sanitation
Symptom
Treatment
Ulcer
Vigor
Viral disease
Objectives
• Identify signs of disease in fish.
• Describe the types of fish disease.
• Identify methods of preventing and treating
fish disease.
What are signs of diseases in fish?
• Diseases may cause fish to:
– Stop growing
– Grow slower
– Even die
• Identifying signs of disease early allows for
treatment of disease in time to reduce the
losses.
• Healthy fish are alert and active.
• Unhealthy fish display symptoms of disease.
– A sign that a disease may exist
Common symptoms of disease
• Lack of appetite
– Fish are active eaters.
– Consume all of the feed rapidly after being
fed.
– A change of eating habits may be a symptom.
• Lack of vigor
– Healthy fish are active and vigorous.
– Vigor is the movement of fish in the water.
Common symptoms of disease
• Skin abnormalities
– Ulcers
• Open sores on
skin containing
pus.
– Lesions
• Result of an
injury.
– Abscess
• Area of the skin
that is swollen
and usually
contain pus.
– Cyst
• Pocket in the
skin that
contains fluid or
dead skin.
Common symptoms of disease
• Abnormal body shape
– Bulging eyes.
– Growths around
fins or mouth.
– Swollen bellies.
http://www.americulture.com/
• Change in behavior
– Healthy fish
behave similarly
from day to day.
– Producer must be
familiar with normal
behavior of fish.
What are the types of fish
diseases?
• Infectious disease
– Can be passed
from one fish to
another.
– Caused by germs
or pathogens.
• Non-infectious
diseases
– Can’t be spread
from one fish
another.
– Not caused by
germs or
pathogens.
What are the types of fish
diseases?
• Dead fish
– Immediately
remove.
– Evaluate for
signs of disease.
www.sun.ac.za/kie/unistel/
aquaculture/
What are the types of fish
infectious diseases?
• Bacterial disease
– Caused by bacteria.
– Usually internal.
– Lab test required to test for disease.
• Fungal disease
– Caused by tiny organisms called fungi.
– Grow on dead flesh.
– Could be a sign of another disease.
What are the types of fish
infectious diseases?
• Viral disease
– caused by a virus.
– often undetectable and difficult to treat.
• Parasitic disease
– Caused by parasites
• animals or plants that live in or on other
animals (hosts).
– Harm hosts by chewing or sucking.
– If live in digestive system steals nutrients from
host.
What are the types of fish
non-infectious diseases?
• Nutritional disease
– Inadequate diet
– Not enough food
– Improper nutrition
– Too much food can cause problems also
• Environmental disease
– Substances in the water
– Include heavy metals, gas or pesticides
What are the types of fish
non-infectious diseases?
• Chemical disease
– Level of a chemical in the water reaches point
that injuries or death occurs.
– Come from pesticides or other pollutants.
• Physiological disease
– Abnormal functions in the organs of the fish.
How can fish diseases be
prevented and treated?
•
Diseases among fish can be controlled in
two different ways.
1. Prevention
•
Keeping fish healthy and free of disease.
2. Treatment
•
Using medication or other practices to help
fish overcome diseases.
How can fish diseases be
prevented?
• Sanitation
– Keeping the water
and facilities clean.
– Washing tanks.
– Ensuring people
don’t introduce a
disease.
• Quarantine
– Separating some
fish from the others
to prevent
diseases.
– New fish are
brought in to a
facility it is common
to quarantine them
for a few weeks.
How can fish diseases be treated?
• Dipping
– Immersing the fish for a few seconds in a
concentrated solution designed to treat
disease.
– Used when a few fish need to be dipped.
– Common dips include:
• Formalin
• salt
How can fish diseases be treated?
• Feed Additives
– Medications mixed in with the feed.
• Bathing
– Similar to dipping.
– Except fish are placed in solution for a longer
time.
http://www.tilapiaseed.com/
How can fish diseases be treated?
• Injecting
– medications may
be injected in to the
fish using a needle
and syringe.
• Indefinite treatment
– adding a low
concentration of a
chemical to the
water over a long
period of time.
http://www.genomar.com/supreme.asp
Review / Summary
• What are signs of diseases in fish?
• What are the types of fish diseases?
• How can fish diseases be prevented and
treated?