fish disease and health management

1. FISH DISEASES AND HEALTH MANAGEMENT
PABITRA BARIK

2. What is Disease?
 Definition: any alteration of the body or one
of its organs so as to disturb normal
physiological function
 opposite of health = unhealthy or dysfunctional

3. Disease free healthy fish shows the following characters:
􀂾 Clean body
􀂾 Erect fins
􀂾 Bright body colour
􀂾 Bright eyed
􀂾 Faster movement
􀂾 Skin and fins intact conditions
Common clinical signs shows by a fish affected with disease:
􀂾 Irregular swimming movement
􀂾 Jumping of the fish
􀂾 Rubbing the body against rough substrate
􀂾 Surfacing on water
􀂾 Refusal of feed
􀂾 Excessive mucus secretion
􀂾 Abdominal swelling
􀂾 Cyst formation
􀂾 Fin erosion
􀂾 Body deformities
􀂾 Gasping air

4. Fish organs affected with disease:
􀂾 External part- i.e. scale
􀂾 Mouth and anus
􀂾 Nostril
􀂾 Eyes
􀂾 Gills
􀂾 Internal organs- digestive tract, liver, kidney, gonad,
etc.

5. Host-Pathogen-Environment Relation
Host Pathogen
Environment
Disease
In the development of disease, three factors interact
Fish Virus, Bacteria
Protozoa, Fungus
Parasites etc
Physico – chemical parameters of pond water and soil

6. Factors affecting on the Health of Fish
Fluctuating Water & Soil Parameters
Quality Fish Seed
Quality Feed & Nutritionally Balanced Diet

7. Loss of
natural Colour
Fins and
Tail Necrotic
Wounds
on the Body
Breaths
with Mouth
Loss of
Stability &
Homeostasis
Fish Comes to
Surface & Swims
slowly very often
Eyes Enlarged
and
Exophthalmic
Gills loose natural
Red colour –Pale in
Colour or Necrotic
Heavy
Mucous on the
Body & Gills
Edging
Loss of
Appetite
Distended
Abdomen – Colon
filled with Fluid

8. COMMON TYPE OF DISEASES IN FRESHWATER FISH
Parasitic Diseases
Fungal Diseases
Bacterial Diseases
Nutritional Deficiency Problems
Environmental Related Problems
Crustacean Parasite
Helminth Parasite
Protozoan Parasites
EUS

9. BACTERIAL DISEASES

10. Tail Rot & Fin Rot
Causative agent: Pseudomonas sp, Aeromonas sp
• Tail & Fins Necrotic
• Fish become ugly due to total necrosis of fins & tail
• Muscles exposed
Symptoms

12. .Mix OTC @ 100 Gms per ton of Fish per Day for 6-7 days
•Reduce stocking Density
• Better management of Water Quality
Treatment

13. Hemorrhagic Septicemia
(Infectious abdominal Dropsy)
Causative Agent: Aeromonas sp.
• Commonly Called as Red Diseases (sores on the body)
• Dropsy
• Colon, Intestine, Anus become reddish in colour
• Eyes protruded
• Pus comes out through anus
• Common in summer season
Symptoms

14. Red Disease

15. Abdominal Dropsy
Aeromonas sp.

16. ULCER DUE TO THE AEROMONAS

17. •Mix 100 mg teramycine tablet/kg feed of Fish for 5-6 days
•Application of 5 ppm Potassium permanganate
•Manage Water quality
• Infected fish should removed from the pond
When dropsy makes its appearance, any dead fish should be
collected, and buried. Those which have been ill are never put into
hybernation together with healthy fish. After the fish have been
removed the tanks should be disinfected with quick
lime and are left dry throughout the winter period.
Treatment

18. Columnaris
(Commonly called as Saddle Back Disease )
Causative Agent: Flexibacter columnare
1. Initial stages exhibit small greyish patches over head, on the
edges of the scales and on the fins, although the gills and lateral
sides of the body may also be affected. A chararacteristic lesion
produced by columnaris is a pale white band encircling the body,
often referred to as saddle back.
2. In the later stage the pathogen penetrates the epidermis and
dermis and forms red ulcerations in the musculature. The gill
filaments disintegrating and gill necrosis observed.
3. Mass mortality of Fish particularly Rohu fish
4. Commonly noticed in Winter season
Symptoms

19. Columnaris

20. •Mix OTC @ 100mg per Ton of Fish per day for 6-8 days
•Reduce Stocking Density
•Water Quality management
•Pond bottom management
Treatment

21. Diseases caused by Fungus
(Fungal Diseases)
Fish disease caused by fungal infection is encountered in
eggs, fry, fingerlings and adult fishes. They are primarily
recorded as secondary invader and are known to attack
the host when it gets injured either mechanically or as a
result of infection other than fungal.

22. Saprolegniasis
(Water mold, Skin Fungus, Cotton Wool Disease)
Saprolegniasis is mainly a secondary infection seen after damage
to the fish integument (skin and gills) caused by parasites, viruses,
bacterial infections and other skin damage. Other predisposing
factors include water pollution and over crowding.
Less commonly saprolegnia can act as a primary pathogen
infecting fish that haven’t shown signs of previous damage.
It is believed that such attacks are temperature-dependant,
usually occurring at low temperatures, possibly as a consequence
of a reduced immune response. As well as being a threat to fish,
Fungus can also affect fish eggs. It is usually the infertile eggs
that are first infected, but if untreated the fungus soon spreads
to nearby, healthy eggs.
Causative Agent: Saprolegnia parasitica

23. Symptoms of Saprolegniasis
1. Fish fungus appears as grey/white patches on the skin or gills of
host fish or eggs that resemble tufts of cotton-wool.
At a later stage they may become brown or green as they
trap sediment or green algae.
2. Microscopic examination shows broad, non-septate (no dividing
cell walls) hyphae of varying diameters.
3. Gills necrotic
4. Brushing against solid objects
5. In severe cases Saprolegnia may actually penetrate into the
muscle tissue.
6. Fishes become lethargic, listless and less responsive to external
stimuli

25. Cotton wool disease

26. •Dry the pond and remove the silt
•Reduce the stocking density
•Reduce Organic Matter
•Apply Formalin @ 1lt + 100 Gms of Malachite Green per
Acre
•Mix Salt @ 50-60 Kgs per ton of Feed for 5-6 days
Treatment

27. Branchiomysis
(Gill Rot)
Causative Agent: Branchiomyces sanguinis for carp
Branchiomyces demigrans for Pike & Tench

28. Symptoms of Branchiomycosis
1. The gills lose their normal red colour and turn yellowish brown
2. The affected gill filaments die, decompose, and fall off.
3.The fish become lethargic, gasp for air, breath with difficulty,
and finally suffocate

30. Effect on Host:
The pathogenic fungus forms long tubule in the gill epithelium
of the fish. The hyphae displace the host tissue and stop the
blood supply to the gills by causing swelling and destruction
of the blood vessels. Large patches of the destroyed gills
become necrotic and fall off.

31. •Dry the pond and remove the silt
•Reduce the stocking density
•Reduce Organic Matter
•Liming the pond @ 50kg/ha
•Apply Formalin @ 1lt + 100 Gms of Malachite Green per Acre
•Mix Salt @ 50-60 Kgs per ton of Feed for 5-6 days
•Bath treatment of the affected fish with Sodium Chloride
@ 3- 5%
Treatment

32. PARASITIC DISEASES
Protozoan
Parasites
Helminth
Parasites
Crustacean
Parasites

33. PROTOZOAN DISEASES
Protozoans constitute one of the most important group of animal
parasites affecting fish. Protozoans are one –celled organisms that
consist of a cell nucleus enclosed by a cell membrane. Many of
them cause fatal disease if the fish are not treated in time

34. Icthyophthiriasis
(White spot disease, Sand grain or gravel disease or Ich)
Causative Agent: Ichthyopthirius multifilis
Symptoms:
1. Minute white spots, nodular in form and in size are visible on
the skin, fins and gills
2. Affected fishes show irritation, erratic movement and
restlessness with tendency to rub on the sides.
3. Heavy Mucous Secretion
4. Gills Necrotic
5. Looses natural colour and stops Feeding

35. Treatment:
•Reduce Stocking Density
•Apply Formalin @ 1 lt + 100 Gms malachite Green per acre

36. Trichodiniasis
Causative Agent: Trichodina reticulata
Symptoms:
1. Colour of the gills turn pale and there is a creamish coating due
to excessive mucus secretion.
2. Heavily infested fishes gradually become sluggish and lose
weight, and very often, there is asphyxia.
3. Fish Glides and Swims erratically and Dies
4. Gills necrotic
5. More acute during summer months

37. Treatment:
•Reduce Stocking Density
•Apply Formalin @ 1 lt + 100 Gms malachite Green per acre
•Sodium chloride bath treatment @ 2-3% till the fishes are
stressed
•Reduce Organic Manure & Load

38. Myxosporidians
Causative Agents: Myxobolus sp
Symptoms:
1. Lives in Alimentary canal & Gills
2. Spores are spindle/ Oval shaped
3. Cysts are commonly seen in Gills as white spots
4. Each cyst contains lakhs of Spores
5. Commonly noticed in winter season -causes respiratory problem
6. Poor Growth

39. Treatment:
• Drying of Pond
• Mix Salt @ 50 kgs per ton of feed for 5 days
•Formalin @ 1.5 Lts per Acre

40. Helminth Parasites
Helminths of the group Monogenea parasite various fish
species causing their growth retardation and mortality.
Their body is dorsoventrally flattened. They have
attachment organ, called haptor at the posterior end,
with varying number of median and marginal hooks.
They are ectoparasites. Generally host specific. Live on the
skin and gill of fish. The grasping hooks on the posterior
end serve to hold on to the skin of the host

41. Helminth Parasites
Dactylogyrus Gyrodactylus
Haptor with 14 marginal hooks,
squamodisc absent
Haptor with 16 marginal hooks,
squamodisc present
The anterior end is provided with two
pairs of eye spots
No eye spots
Oviparous, laying eggs and live as
parasites, particularly in gills
Viviparous and liberates live young
worms
Head is scalloped V shaped head (bilobed)
Parasitize particularly the gills Parasitize the skin and more rarely
the gills

42. External symptoms of Dactylogyrus infection:
1.The colour of gills fade and there is excessive secretion of mucus
causes reparatory problems.
2. At the site of attachment, gill tissue erosion occur
3. Growth reduction of affected fishes
4. In heavy infestation fishes become feeble and rest near
the pond side
Treatment:
•Drying of Pond
•Low Stocking Density
•Application of 15 ppm formalin in pond
•Sodium chloride bath treatment @ 3- 5% for 10 – 15 minutes

43. GYRODACTYLOSIS

44. External symptoms of Gyrodactylus infection:
1.Fading of the normal body colur
2. Dropping of scales
3. Excessive mucus secretion
4. Growth reduction of affected fishes
5. In heavy infestation fishes become feeble and rest near
the pond side
Treatment;
•Drying of Pond
•Low Stocking Density
•Application of 15 ppm formalin in pond
•Sodium chloride bath treatment @ 3- 5% for 10 – 15 minutes

45. Crustacean Parasites
Crustaceans are almost without exception aquatic animals which
breath by means of gills . The grater part of the crustaceans
undergo a metamorphosis with frequently includes a nauplius
stage. Sexual dimophism is common among parasitic crustaceans.
Crustacean parasites are frequently found to infest fishes.
Infestation of fishes in confined water very often causes serious
diseases outbreak.

46. Argulosis
(Fish lice)
Causative Agent: Argulus foliaceous

47. External Symptoms:
1. The adult parasite is oval, flat, transparent to whitish with two
conspicuous black spots. It attaches to the skin and fins of the
fish via suckers and feeds on blood.
2. It is visible moving freely on the surface of the host fish.
3. Affected fishes are restless with erratic swimming behaviour
4. Loss of appetite
5. Attachment sites shows sign of ulceration
6. In case of severe infection, growth retardation and sometimes
mortality occur.
7. Flickering and Gliding of Fish . Infested fish rub on submerged
objects or bottom substrates in an attempt to dislodge the parasite
from their skin
8. Heavy mucous on the body

48. Fish Lice

49. Propagation:
Mature Argulus sp inhabit the host fish. After copulation the
female leaves the host and lays sticky eggs (20 – 250) on the
submerged vegetation, rocks objects etc. Eggs hatch into larva
and develops into adult form after a few days. The entire life cycle
Takes 40 – 100 days depending on the water temperature. All the
Free living stages are parasitic to fish.

50. •Reduce Organic Matter
• Apply Cypermethrin @ 100 ml per acre
• Apply 1 – 2 ppm dichlorves (Nuvan)
• Mix Ivermectin ( 0.1 %) in Feed @100-125 Gms per ton of
Fish for 5days
Treatment

51. Ergasilosis
Causative Agent: Ergasilus sp.

52. Symptoms:
1.Infestation occurs in gills, buccal cavity, operculum and fins.
2. They look like whitish, elongated objects on the gill filaments.
3. They damage the fish by digesting its epithelial cells
4.Surfacing, lethargy and restlessness of affected fish occur
5. Since the parasites often change position on the fish, the gills
Suffer widespread damage.
6. Secondary infections often occur, particularly with fungus.
7. Heavily infected fish suffer from anemia, become emaciated,
and are susceptible to many other diseases.

53. Treatment:
•Application of 5 ppm Potassium permanganate
•Provide Balanced Diet
•Reduce Stocking Density
•Sodium chloride bath treatment @ 2-3% for 15 minutes

54. Lernaeosis
(Anchor Worm)
Causative Agent: Lernaea sp

55. Symptoms:
1. Fish body cavity and head region is affected by Lernaea sp
2. In light infestation the fishes are restless and rub against the
sides and bottom of the pond due to irritation.
3. Heavily infested fishes become moribund with erratic
movement and emaciation.
4. Parasite penetrates in the body and swallows the tissues
and make host weaker and emaciated
5. More acute in winter season

56. Treatment:
•Sodium chloride bath treatment @ 2- 5% for 15 minutes
• Provide balanced highly vitaminised Feed
• Reduce Stocking Density

57. Epizootic Ulcerative Syndrome (EUS)
 Mixed Infection of Bacteria, Fungus, Protozooans
 Black & White fish are affected in winter season
 Reddish & Grayish wounds are noticed on the Body
 Mass mortality of Fish noticed

59. • Apply Quicklime @ 50 kgs + 30 kgs salt per acre
•Sulphadiazine application in feed @ 100mg/kg of feed
• Mix OTC( 10 %) @100 Gms + Furazolidon @ (20%) @50 Gms
per ton of Fish per day for 6-7 days
•Application of CIFAX gives good result
Treatment

60. Other problems
Environmental
problems
Nutritional
Deficiency Problems

61. Nutritional Deficiency Problems
Problem Symptoms Deficiency
 Lordosis Wrinkle of Body Vit. C ,A, P,Mg
 Catract Fatty Layer in Retina
Methionine,Vit.A
 Necrotic Fin & Tail Rot Lysine,Vit. A&C
 Fatty Liver High Fat in Liver Cholin, Stale
feeds
 Blood Spots Blood spots at Fin Riboflavin &
bases Pantothenic
Acid

62. Environmental problems
1. High Nitrite:
 > 01 ppm of Nitrite in the water Toxic to fishes –
causes Respiratory problem
 Gills become Chocolate colour
Treatment:
•Water Exchange
•Apply Quicklime @ 30-40 Kgs + 40 kgs per acre
•Use Bioremediators

63.  >0.1 Free ammonia is Toxic to Fish
 Fish Becomes lethargic
 Surfacing during early morning
 Stops Feeding
 Mass Mortality
Treatment:
•Water Exchange
•Apply Zeolite @ 10-15 Kgs per Acre
Ammonia Toxicity

64. Oxygen Deficiency
 < 2 ppm of Oxygen is harmful to Fish
 Surfacing & Air Gulping during early morning
 Mass level Mortality
 Fish Colour fades and become pale
Treatment:
• Exchange with freshwater
• Apply Calcium Peroxide @ 500-600 Gms per Acre
• Apply Hydrogen Peroxide @ 500-750 ml per Acre

65. Disease Prevention Measures
• Good water & Soil Characteristics
• Quality and balanced Diet
Protein: 18-20 %
Fat : 3-4 %
Energy: 3500-4500 Kcal per kg Feed
• Better management Practices
• Drying of Pond and Removal of Silt in everyyear
• High stocking Density should be avoided
• Removal of / Prevention of Entry of Molluscs ,Weed Fish
• Selection of Quality Fish Seed
• Treatment of Fish seed with 1% salt and Potassium
permanganate before stocking

66. Probiotics are dietary supplements of live microorganisms
thought to be healthy for the host organism.
According to the currently adopted definition by FAO/WHO,
probiotics are: "Live microorganisms which when administered
in adequate amounts confer a health benefit on the host".
Lactic acid bacteria (LAB) and bifidobacteria are the most
common types of microbes used as probiotics; but also certain
yeasts and bacilli are available.
PROBIOTICS

67. SOME USEFUL CHEMICALS
AND MEDICINE
TO CONTROL FISH DISEASES

68. Formalin
• Aqueous solution of of 37 – 40% by weight of formaldehyde gas
• It kills protozoan, fungal and helminth parasites
• Formalin is highly toxic to phytoplankton and oxygen depletion
may occur in pond due to algal death
BKC (Benzalkonium Chloride)
• It is a compound of mixture of alkyl dimethyl benzyl ammonium
chlorides.
• It has anti-bacterial and anti-fungal property
• This compound is available as 50% and 20% solution
commercially.
• Dosage for treatment of pond water is 0.5 – 1.0 ppm for 50%
solution and 1.0-2.0 ppm for 20% solution

69. Potassium Permanganate
•It is a strong oxidising agent with good antimicrobial activity
• It releases nascent oxygen while desolving in water.
•The nascent oxygen destroys micro organisms as well as organic
organic substances, through its oxidising action
•Do not use Potassium permanganate frequently since the manganese
metal and manganese dioxide may settle on the gill surface of fish/
prawn and interfere with their respiration
Malachite Green
• It is greenish crystal with metalic lusture. It is very soluble in water
The water solution appears as blue-green
* It is very effective against fungal disease.

70. Zeolite
•It occurs naturally in sedimentary and volcanic rocks
•Commercially it is found in the form of grayish-powder form
•The cations in zeolite are mobile and capable of undergoing
ion exchange. Therefore zeolite act as a cation exchanger. It
can selectively absorb NH4
+ in water
Acriflavine
• It is also known as 3,6-Diamino-10-methylacridinium chloride
• It is an antiseptic, protozoacide.

71. Oxytetracycline (OTC)
• It is a broad-spectrum antibiotic against gram-positive and gram-
negative bacteria
• It is also effective against some protozoan infections
• It inhibits the synthesis of bacterial proteins. Thus the growth
of bacteria is controlled
• It is readily absorbed from the intestinal tract and can get into
bacterial cell quickly. Hence it is more effective when given orally

72. VACCINATION