This study deals with a field survey about fish parasites in Thakurgaon-5100, Bangladesh and their impact on fish culture system with adequate information. This study will help to identify those fish parasites and take necessary precaution measure for dealing with these parasites.

1. Fish Parasitological Studies of Thakurgaon,
Bangladesh and Their Impact on Fish Culture
Md. Atick Chowdhury
B.Sc. Fisheries (Hons.), Level: 02, Semester: 02, Faculty of Fisheries
Sylhet Agricultural University, Sylhet-3100

2. 1
Introduction:
Bangladesh is one of the world’s leading fish producing countries and it’s total
fish production shows a consistently increasing trend from the fiscal year
1983-1984 to 2011-2012 and the production increased more than four times
(754,000 MT in 1983-1984 to 3,262,000 MT in 2011-12). Indian major carps like
Catla catla, Labeo rohita, and Cirrhinus mrigala are considered as the major
cultivable fish species in inland aquaculture of Bangladesh and it contributes
around 85.29% of total pond fish production of Bangladesh. Along with
carps all the freshwater species found more or less to suffer with different
types of diseases while 15%-20% are associated with parasite infestation.
Indian major carps are highly susceptible to disease in comparison to Chinese
and European carps. The intensity of fish parasitic infection is greatly
influenced by seasonality, which affects host ecology as well as physiology.
Intense parasite infection can cause ulceration and upset the normal course of
reproduction. Parasites interfere with host nutrition, metabolism and secretary
functions of the alimentary canal and can even damage the host nervous
system. All these effects may reduce normal growth of the fish and finally
induce the host mortality.
Parasite:
The term of parasite is originated from two Greek words ‘para’ means ‘beside’
and ‘sitos’ means ‘food’. So, parasites are those animals which cling to
relatively large animals of different species externally or internally for food and
also for completion of their life cycle. The parasites are metabolically
dependent on host.
Example: Lice
Fish Parasite:
The parasites which cling to fish body externally or internally for food and also
for completion of their life cycle is called fish parasite.
Example: Tape worm
Methodology:
Fish parasites are available all across the country. The type of parasite in or
clinging to a host fish may be different according to season and place. So, the
investigation of fish parasites according to area basis can be a great document

3. 2
for parasitological study. This investigation can ease our work to gather
information about the fish parasites available in our country, their effect,
occurance period, problem regarding to production, preventive measures etc.
Description:
My hometown is Thakurgaon under Rangpur division. So, my task was to figure
out fish parasites available in my locality and their impact on fish culture
system. So, during Eid vacation, I went to the nearest District Fisheries Farm
and discussed with the present District Fisheries Officer (DFO), Md. Abdus
Sattar there about the topic. Later, I also discussed my assignment topic and its
subject matter with Md. Latifur Rahman, District Fisheries Officer, Lalmonirhat
who is the previous DFO of Thakurgaon. I have tried to find out all important
and adequate information about my given task and I think, I am quite
successful in this matter.
Parasites Available in My Locality:
Through my investigation, I have figured out fish parasites like Argulus sp.¹,
Lernaea sp.², leech ², Ichthyophthirius multifiliis mainly and sometime round
worm² are also available in my locality.
The description with necessary information about available fish
parasites in my locality are given below.
1. Argulus sp.
Classification:
Kingdom: Animalia
Phylum: Arthropoda
Class: Copepoda
Order: Argulidea
Family: Argulidae
Genus: Argulus
Species: Argulus sp.
Common Name : Japanese fish louce
Parasite Type : Ectoparasitic
Figure: Argulus sp.

4. 3
Morphology:
i. Light brown in colour
ii. 4 mm to 9 mm long and 3 mm to 6 mm wide
iii. It has a stumpy tail
iv. Flattened creature, spherical shape
v. Two pairs of antennae present
vi. Two suckers for attaching to the skin of the hosts
vii. Large hollow preoal sting or proboscis present to penetrating and feeds
on blood of its hosts
Distribution:
 Mostly the carp species are affected by Argulus
 Catla catla is very much affected
 Occurs also in aquaria
Symptoms:
 Can be seen with naked eye
 Frequent rubbing or flashing
 Localised redness
Production Problem:
 Severely damage host, integument affected
 Loss of appetite, sometime resulting death
 Affect growth rate
Figure: Argulus sp. on fish skinFigure: Argulus sp. on fish fin

5. 4
Treatment:
 Pyrethum is a good therapeutic substance, dose is 20-100 ppm for 50
minutes
 Bytex
 Potassium permanganate (KMnO4)
2. Lernaea sp.
Classification:
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Crustacea
Class: Maxillopoda
Subclass: Copepoda
Order: Cyclopoida
Family: Lernaeidae
Genus: Lernaea
Species: Lernaea sp.
Common Name : Anchor worm
Parasite Type : Ectoparasitic
Morphology:
i. Anchor worms (Lernaea) can be seen with the naked eye
ii. In female behind mouth a well developed hold fast organ present
iii. The elongate neck and trunk carry the four pairs of legs
iv. If anchor penetrate in body, it never be removed
v. Tiny white-green or red worms in wounds
Figure: Lernaea sp.
Figure: Lernaea sp. on fish skin Figure: Lernaea sp. on fish gill

6. 5
Distribution:
 Found almost all across the country
 Common in closed water and open water fishes
Symptoms:
 Can be seen with naked eye
 Frequent rubbing or flashing
 Localised redness
 Inflammation on the body of the fish
Production Problems:
 Breathing difficulties
 General lethargy
 Weight loss
 Filthy flesh and outer side of fish
 Even death occurs to fish
Treatment:
 Potassium permanganate
 Salt dip
 Formalin dip
 Modern antiparasitics
 Salt in the aquarium at 1 to 2 tablespoons may help to prevent
secondary infection
3. Leech (Piscicola geometra)
Classification:
Kingdom: Animalia
Phylum: Annelida
Class: Clitellata
Subclass: Hirudinea
Genus: Piscicola
Species: Piscicola geometra
Common Name : Leech
Parasite Type : Ectoparasitic
Figure: Piscicola geometra

7. 6
Morphology:
i. Segmented worms
ii. Both oral and ventral sucker present
iii. Ventral sucker is only for attaching to the host
iv. Body surface divided into 102 annuli
Distribution:
 Mainly occurs during winter
 Found in both marine and freshwater environment
Symptoms:
 Can be seen with naked eye
 Frequent rubbing or flashing
 Localised redness
Production Problems:
 Weight loss
 Severe when the parasite remain attached for long time
Figure: Piscicola geometra on fish skin
Figure: Oral sucker of Piscicola geometra

8. 7
Treatment:
 Can be removed by hand using a fingernail or other flat, blunt object to
break the seal of the oral sucker at the anterior end of the leech
 Common, but medically inadvisable techniques to remove a leech are to
apply a flame
 Chemical such as alcohol, vinegar, lemon juice, insect repellent, heat
rub, or certain carbonated drinks
5. Ichthyophthirius multifiliis
Classification:
Kingdom: Animalia
Phylum: Ciliophora
Class: Oligohymenophorea
Order: Hymenostomatida
Family: Ichthyophthiriidae
Genus: Ichthyophthirius
Species: Ichthyophthirius multifiliis
Common Name : Freshwater ich
Parasite Type : Ectoparasitic
Morphology:
i. Body oval to round but very elastic, 0.50 μm to 1mm in diameter
ii. Uniform ciliation
iii. A large crescent shaped macronucleus present (horseshoe-shaped
nucleus)
iv. The adult parasite moves slowly by tumbling but the immature forms
(tomites) are smaller, translucent, and move quickly
Figure: Ichthyophthirius sp.
Figure: Ichthyophthirius multifiliis on fish

9. 8
Distribution:
 Indian major carps (Rui, Catla, Mrigel) are mainly affected
 Most common and persistent diseases in fish
 Life cycle of Ichthyophthirius multifiliis is highly dependent on water
temperature, and the entire life cycle takes from approximately 7 days
at 25 °C (77 °F) to 8 weeks at 6 °C (43 °F)
Symptoms:
 Anorexia (loss of appetite, refusing all food, with consequential wasting)
 Rapid breathing
 Hiding abnormally
 Not schooling (in schooling fish)
 Resting on the bottom
 Flashing
 Rubbing and scratching against objects
 Upside-down swimming near the surface
 Infected fish have small white spots on the skin and gills
Production Problems:
 If not controlled, there is a 100% mortality rate of fish
 Low quality of flesh and gill of fish
Treatment:
 Formalin (2000 ppm for 1 hour 15-40 ppm applied to ponds)
 Malachite green (0.1-0.15 ppm or 0.05 ppm mixed with formalin 50 ppm
applied to ponds)
 Heat treatment can be highly effective
 Methylene blue
 Chelated copper
 Copper sulfate
 Potassium permanganate
 Quinine

10. 9
4. Round Worm (Anisakis sp.)
Classification:
Kingdom: Animalia
Phylum: Nematoda
Class: Secernentea
Order: Ascaridida
Family: Anisakidae
Genus: Anisakis
Species: Anisakis sp.
Common Name : Round worm
Parasite Type : Endoparasitic
Morphology:
i. Need multiple host during life cycle
ii. Vermiform body plan, round in cross section and lack of segmentation
iii. Mouth located anteriorly, and surrounded by projections used in feeding
and sensation
Distribution:
 Found in pond water fishes during winter
 Uncommon where cetaceans are rare
 Larval anisakids are common parasites of marine anadromous fish, eg.
salmon, sardine
Symptoms:
 Loss of appetite
 Abnormal movement
Figure: Anisakis sp.
Figure: Anisakis sp. in fish

11. 10
Production Problems:
 Allergic reactions to chemicals left by the worms in fish flesh
 Weight loss
Treatment:
 Albendazole tablet or liquid
Conclusion:
During the study period, a total of four ectoparasite species and one
endoparasite species were identified from the field study in Thakurgaon
district. The highest peak of parasite prevalence (%) was found in the host of
Labeo rohita in winter while the lowest was found in Catla catla in summer.
This might be due to stocking density, temperature along with other
physicochemical parameters as well as management practices maintained.
However, the total economic loss due to parasite diseases has been estimated
BDT 35,552.50 ha-¹ yr-¹ in Bangladesh³. Therefore, management of these
parasitic diseases should be given top priority to save the fish farm and
industry from this huge economic loss every year at farmer level.

12. 11
References:
1. Md. Abdus Sattar, District Fisheries Officer, Thakurgaon Sadar,
Thakurgaon-5100
2. Md. Latifur Rahman, District Fisheries Officer, Lalmonirhat (Previous DFO
of Thakurgaon)
3. "Parasitic Diseases and Estimation of Loss due to Infestation of Parasites
in Indian Major Carp Culture Ponds in Bangladesh", Md. Shirajum Monir,
Nazneen Bagum, Shafiqur Rahman, Mohammad Ashaf-Ud-Doulah,
Anuradha Bhadra, Shuvho Chakra Borty
4. "Wikipedia", the free encyclopedia