What is bacteria? Bacteria shape Types of bacteria Difference between gram-positive and gram-negative bacteria Common symptom Causes Bacterial disease in fish Furunculosis Columnaris Dropsy Vibriosis Tuberculosis Bacterial gill diseases Fin rot / tail rot

1. GOVT. E.R.R. P.G. SCIENCE
COLLEGE
DEPARTMENT OF ZOOLOGY
BACTERIAL DISEASES IN FISH
SUBMITTED TO:
DR. RASHMI SAO
SUBMITTED BY:
PRIYANKA DUBEY
210630
MSC IV SEM
SUBJECT - AQUACULTURE AND FISHERIES

2. What is bacteria?
Bacteria shape
Types of bacteria
Difference between gram-positive and gram-negative bacteria
Common symptom
Causes
Bacterial disease in fish
oFurunculosis
oColumnaris
oDropsy
oVibriosis
oTuberculosis
oBacterial gill diseases
oFin rot / tail rot

3. • Unicellular or single celled microscopic organisms
• Cell membrane made up of cellulose and chitin
• Vacuoles
• Gram positive and negative
• Cell walls are thick and thin
• Lack nuclei and other organised cells structure
• Some bacteria are pigmented

5. Characteristics Gram-positive Bacteria Gram-negative Bacteria
Cell Wall Single layered smooth cell wall A double layered WAVY cell wall
Cell wall thickness The thickness of the cell wall is 20 to 80
nanometer
The thickness of cell wall is 8 to 10 nanometer
Peptidoglycan layer It is a thick layer / also can be multilayered It is a thin layer / often single layer
Teichoic acid Presence of teichoic acid Absence of teichoic acid
Outer membrane The outer membrane is absent Outer membrane is present (mostly)
Porins Absent Occurs in outer membrane
Mesosome It is more prominent It is less prominent
Morphology Cocci or spore forming rods Non spore forming rods
Flat chala structure 2 rings in basal body 4 rings in basal body
Lipid content Very low 20 to 30%
Lipopolysaccharide Absent Present
Toxin produced Exotoxins Endotoxin and exotoxin
Resistance to antibiotics More susceptible More resistant
Examples Staphylococcus, streptococcus, etc Escherichia, Salmonella, etc.

7. • Lethargic swimming
• Loss of appetite
• Respiratory distress
• Jumping from the water
• Colour of gill changed
• Fins become frayed

8. • Poor water quality
• Fluctuation in temperature
• Improper nutrition
• Access waste deposition

9. • Furunculosis
• Columnaris
• Dropsy
• Vibriosis
• Tuberculosis
• Bacterial gill diseases
• Fin rot / tail rot

10. Causative agent – Aeromonas salmonicida
• Furunculosis is highly contagious disease that affects fish
of all ages.
• The infection causes high mortality in salmonids though
some other species of fish are affected.
• Horizontal transmission occurs via the water column but
also through direct fish-to-fish contact and animal
vectors.
Pathological sign –
• Furuncles or boils involving skin and muscle progressing
to lesions.
• Haemorrhages on the skin mouth and fin bases.
• Darkening of body colour and pale gills.
• Stomach filled with mucus, blood.

11. Treatment
• To drain the pond andtreat it with slaked lime.
• Treatment is done by removing the severely infected fishes from the
pond and by supplying food containing antibiotics like introfurons or
sulphonamides etc.
• Disinfection may be done with 0.015% solution of merthiolate or 0.185%
solution of acriflavine 1% provindon-iodine solution is most
recommended once owing to its relatively less toxicity compared to
other disinfectants.
• Iodine is used to decontaminate the surface of fertilised eggs to
prevent vertical transmission (passage of infection from parent to
offspring).

12. Causative organism – Flexibacter columnaris /
Chondrococcus columnaris
• often mistaken for a fungal infection because of its
mold-like lesion.
• columnaris is a common bacterial infection in
aquarium fish particularly live breeding fish and
catfish.
Symptoms –
• White spots on mouth, edges of scale and Fins.
• Fins disintegrate beginning at the edges.
• ‘Saddleback’ lesion near the dorsal fin.

13. Treatment –
• Add antibiotic in water.
• Normally used antibiotic include the chloramphenicol (10ppm
repeated at 2-5 days interval) and Furance (0.1-0.3ppm) in which
the infected fishes with cotton mark disease are kept for a long
time bath.

14. Causative agent - Pseudomonas puntata
• Dropsy is an old medical term that was once used to
describe swelling due to accumulation of fluids in the
tissues or body cavities such as the abdomen fish suffering
from dropsy often have a hugely swollen belly.
• It was the most fairly disease in carp culture.
Symptoms–
• Swollen belly
• Scale standout
• Eyes bulge
• Anus becomes red and swollen internal organs are affected
most notably they liver and kidneys
• Spine may become curved
• Fish hangs near the surface

15. Treatment –
• Removal and complete destruction of fishes followed by draining drying and
disinfecting the fish pond with quick line is suggested to prevent spread of
disease the.
• Infected fish may be curd by a 2 minute dip in 5mg/ kmno4 solution.
• Resistant strains bacteria may be killed by applying streptomycin or
chloromycetin or oxytetracycline along with supplementary food or by
injecting the severely infected fishes.

16.  Causative agent – Vibrio anguillarum
• This is, shaped bacterium it enters the animal via their food
and attacks the gastrointestinal tract.
• Found in all species in salt water.
• It multiplies in the skin of salmonids but the toxins
produced act on the circulating blood cells causing severe
anemia.
• This disease occurs more than readily at temperature
above 11 degrees celsius.
 Symptom –
• Large bright coloured body lisions in this skin and muscles.
• Gills may bleed with slightly pressure.
• Inflammation of intestinal tract.
• Eye problems with cloudy eyes leading to pop-eye and
finally eye loss.

17. Treatment -
• Dip treatment in copper sulphate solution and application of antibiotics with
artificial food may be considered as curative measures for vibriosis.

18. Causative agent - mycobacterium piscium
• A bacterium closely related to mycobacterium
tuberculosis called mycobacterium piscium can
be present in wild caught as well as captive bred
fish and stay lurking in our aquariums without
us ever realising it.
• Fish can be treated with the same drugs as
humans get when they become infected by
mycobacterium piscium, example kanamycin
Symptom –
• Fin rot, waxy coat body, ulcer on body.
• Nodules in the internal organs
• Loss of appetite
• Loss body weight
• Loss of scales loss of colours

19. Treatment –
• Dip treatment for one minute in 1:2000 copper sulphate solution
for 3-4 days may be useful.
• Alternatively the fishes may be destroyed and the pond sterilized
with KMnO4 or with soaked line restocking.

20. Causative agent – Myxobacteria
• Colonization of damaged gills by these
organisms in the condition known as “bacterial
Gill disease”.
• This reduces the ability of the gills to supply
oxygen to the blood and results in mortality left
unchecked.
Symptoms –
Swelling in gill lamellae
Change in gill colour this

21. Treatment –
• Application of antibiotics like neomycin chloramphenicol etc. may be
useful in treatment of bacterial gill disease in fishes

22. Causative agent – Myxobacteria
• Fin rot is one of the most common.
• It is caused by several types of bacteria and
often occurs concurrently with other diseases.
Symptoms -
• Finn edges turn white.
• Fin fray.
• Bases of fin inflamed.
• Entire fin may rot away.

23. • Treatment –
• Move sick fish to hospital tank.
• Feed fresh high quality food.
• Treat with antibiotics (MARACYN-2, a ten day course is ideal for
ensuring the infection is eradicated).
• Terramycin has proven to be quite effective but as both a bath and
when used to treat foods for internal infection.

24. • Perform regular water changes
• Keep the tank clean
• Clean the filter regularly avoid overcrowding the tank.
• Use flake foods within one month of opening.
• Use disinfect nets and other equipment.

25. • https://www.msdvetmanual.com/exotic-and-laboratory-
animals/aquarium-fish/bacterial-diseases-of-fish
• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6295991/
• https://www.slideshare.net/sanchuyadav/bacterial-disease-of-fishes
• YOUTUBE
• GENERAL AND APPLIED ICHTHYOLOGY – S.K. GUPTA & P.C. GUPTA