study in diseases of fish: fin-rot—a bacterial disease of fins of fish
TRANSCRIPT
STUDY IN DISEASES OF FISH: FIN-ROT-- A BACTERIAL DISEASE OF FINS OF FISH
BY DR. H , ~ I ] ) ICHmv, M.Sc., LL.B. (PUNJAB), P~.D. (CANTAB.) (Fisheries Research Officer, Pwnjab, Lyat~p~tr)
lZeceived October 13, 1939 (Communicated by Dr. B. L. Bhat.ia, I).SC., F.Zr
I~r l~ovember 1938 heavy mor ta l i ty occurred among Gourami fingerlings (O@horme~cus gouri imy Lacdp~de) when these were being t r anspor ted by canal from ~ a d r a s Fisheries Farm, Sunkesula to Kurnool T o w n - - a distance of 17 mi les - - in a " live-car". 1 The fingerlings, before despatch, had been " condit ioned" for a day or two, i .e., had been confined in a " condi t ioning- car"2--a wooden framed box with wire ne t t ing on all s i d e s - - k e p t in wate r and starved.
In all t he dead f ry it was observed t h a t the caudal fin was frayed, and observations made on the dying fingerlings, en rou~e from /~m'nool Town to Delhi, showed t h a t the epidermis from the caudal fin was g radua l ly being eaten off and the caudal rays were consequent ly ge t t ing exposed. I n some cases the dorsal and anal fins had also been affected (Plate x v n I , Figs. 1-4). The sick f ry swam near the surface of the water in the container , lost the i r balance on the caudal fin becoming f rayed upto its base, t u rned upside down and died, the dead ones sinking to the bottom.
The author had noticed similar symptoms among Rainbow t rou t f ry when they were at tacked by fin-rot? I n order to inves t iga te the m a t t e r in detail, f reshly dead Courami fry were t aken to the Imper ia l Agricul tural Inst i tute , New Delhi, and examined by the Assis tant Bacteriologist. His preparat ion from affected caudal fin (Plate X V I I I , Fig. 5) showed exact ly similar rod-shaped bacter ia as had previously been observed by the au thor in Rainbow t rou t suffering from an a t t ack of fin-rot.
i ,, Zive-car " is a wooden barrel, conical at one end and round at the other~ with a smMl opening at one side. It is made to float in water and has been in use for trans. port of a]ive fish by IVf~dras Fisheries Department for a number of years.
" Condi~ion.ing-car " is similar to " live-car '" used in the Punjab for keeping fry under observation. Its photograph was given by the author in Jouvn. Bomb. NaL HisL Soc, 192~, 29, [No. 4.
a I-[amid Khan, " Notes on the diseases of Trout at the 1Vfahili l~f~tchery~Kulu - Punjab", ibi&, 1939, 40, 4, 653-.56.
369 B6 F
370 Hamid Khan
I~,ocuf~tion of Rain.bow Trou~ F' O,
Some dead Gourami fingerlings were brought in water to 1~yalllmr and examined by the Agricultural Bacteriologist. Saprophytic bacteria., in addition to pathological ones, hz.d also mc:de their appearance by that time. To obtain pure culture of pathological bacteria, healthy Rainbow i;~out fry measuring fIom 52 r a m . to 66 ram. in length, blought fxonl Puni~ b Govern- ment Fish Fa rm at ~{adhopur, were inoculatcd on the 9th l~ow.mber 1938, at i-30 p.m. with bacteria from the affected pa~ts of the dead Gourami as follows : - -
(i) The caudal fins of three healthy Rainbow trout fry were scratched with sterilized needle and rubbed with the caudal :Iin of the diseased Gourami fingerling, and
(it) three Rainbow trout fry, with scratched caudal tins, were simply placed in contaminated water in which the diseased fish had been lying.
Four Rainbow trout fry with scratehcd caudal fins were kept as control in uncontaminated water. The experiment was conducted in aquaria in F~sheries Research Laboratory at Lyallpur. Temperature of water ranged from 62 ~ F.-66 ~ F. and source of water supply was ordinary tap water. Aeration of water in the aquaria was maintained by Semper's Aerating Apparatus.
_Progress of the Disease
Rai~zbow Trout 2Cry No. / . - -On the 10th November, at 8 a.m., fry No. 1 (Plate XIX, Fig. 2) showed slightly whitish area on the free extremiW of its caudal fin. On the l l th, it was seen swimming near the smfa.ee of water and its caudal fin was slightly exposed at its extremity. On the 12th, the rays of its caudal fin were almost totally naked and the disease had spread with great rapidity to its caudal peduncle and anal tins. The caudal fin rays got disintegrated.and soon after the f ry lost its balance, and while i t was dying its caudal fin was cut for culture of bacteria. The fry died on the 12th ~ovember at 2-30 p.m., i.e., after about 70 hours after inoculation and 5r hours after the symptoms of the disease became visible externally.
Rainbow Trout Fry No. 2 (Plate XIX, Fig. 3).--Showed" external ~ymptomss" " of the disease on the l I t h November, at 8 a.m. On the 12th the tht rays of the caudal fin had become exposed and on the 13th, the caudal tin, as well as the caudal peduncle, were seriously affected. The eolour of the fry had become dark and it swam near the surface of the water. The fry died
,~tudy kz Diseases o f Fz's~ : Fin-2?ot 371
at 11 a.m., on the 13th November, i.e., 90 hours after inoculation and 51 horns after the disease had become visible externally.
Rai~bow Trout Fry No. 3 . - - In Rainbow trout fry No. 3 (Plate X I X , Fig. 4), external symptoms were visible on the 12th November and the fish died early in the morning on the lCth.
Rainbozv TJ, out F'~ T No. 4.- -Out ~f the second lot, in which the caudal fin had been scratched but not inoculated and the fry had been put in contami- nated water, Rainbow trout fry No. 4 (Plate X I X , Fig. 5), showed external symptoms on the l l t h November. On the 12th, its caudal fin rays were slightly exposed and on the 13th it died at 11 a.m.
Rainbow Trout .Fry Nos. 5 and &--Rainbow trout fry Nos. 5 and 6 showed external symptoms of the disease on the 12th November and were found dying on the l~th. Upper lobe of the caudal fin (Plate N I X , Figs. 6 and 7), had partially disintegrated and caudal peduncle was affected upto the base of the adipose fin. The infection had spread to the anal fin too. Fry No. hdied on the 12th, at 12a.m., and No. 6 at 3p.m. , on the 14th November.
Rainbow trout fry kept as control did not show any symptoms of the disease.
Rainbow Trowel .Fry No. 7.- -On the 14th November, when all inocu- lated fry, as well as those which had been put in contaminated water, had died, one fry fiom the control was transferred to the contaminated water and its caudal fin, without being scratched, was iubbed against the caudal fin of recently dead Rainbow t lout fry at ].2 a.m. On the 15th, the disease appeared on its adipose fin and the tissues at the Base of this s were seriously affected (Plate XIX, Fig. 8). The fry died on the morning of the 16th November.
Rai~,bow Tror Fry No. 8.--On the !6 th November, at 9-30 a.m., another fry from the control was inoculated on its caudal fin after it had been scratched, by rubbing it against tile caudal fin of recently dead Rain- bow trout fry. On the i7th the fry showed disease at the base of the caudal fin and the caudal peduncle was seriously affected (Plate X I X , Fig. 9), On the 18th at tempts were made to cure the fry by put t ing it in copper sulphate soh~tion (1 : 5,000), but *he disease had advanced too much, caudal fin rays had disintegrated and the tissues at the base of the caudal fin had been invaded. Consequently the fry died on the morning of the 19th November.
The Rainbow trout fry infected wi.th the disease, thus, died within 70-118 hours after inoculation and within 50-55 hours after the external appearance of the disease.
Tab
lesh
owin
gth
eP
rogr
ess
ofF
in-r
otD
isea
sein
Rai
nbow
trou
tfr
yin
ocul
ated
wit
hth
eD
isea
sefr
omD
isea
sed
Gou
ram
i(O
sphr
omen
usgo
uram
iL
acep
ede)
.
e» 'l N
Date
Tem
per
atu
reM
orn
ing
-No
cnN
o.1
*le
ng
th?
42m
m,
No
.24
6m
m.
No
.35
0m
m.
No
.44
8m
m.
No
.55
2m
m.
No
.658
ram
.N
o.7
52
mm
.N
o.8
51
mm
.
No
effe
ct.
No
effe
ct.
No
effe
ct.
The
soth
roe
fry
wer
t!p
ut
itt
cont
amin
ated
wa
ter
at4-
30p
.m.
No
effe
ct.
No
effe
ct.
All
the
thr{
'{!fr
yw
ere
inoc
ulat
edat
4-30
p.m
.
Sli
ghtw
hit
ish
area
onlth
efr
eeex
trem
ity'
ofca
udal
fin.
680
F.
610
F.-
64
°F.
9-11
-38
I1
0-1
1-3
8
II-I
I-3
862
°F
.-6
6°
F.S
wim
min
gn
ea
rsu
rfa
ce,
colo
urd
ark
,ep
ider
mis
fro
mtip
iof
caud
alfi
nea
ten
off
and
rays
exp
ose
d,
Cau
dal
fin
slig
htly
af
fect
ed.
No
sym
pto
ms
visi
ble
exte
rnal
ly.
Cau
dal
fin
slig
htly
affe
cted
.
No
sym
pto
ms
visi
ble
exte
rnal
ly.
No
sym
pto
ms
visi
ble
exte
rnal
ly.
::r:: ll' S 0.:
12
-11
-38
62°
F.-
66
aF.
Cau
dal
fin
two-
thir
dina
ked,
Up
per
lobe
]di
sint
egra
ted.
caue
l-I'
alpe
dunc
leaf
fect
ed.
Cau
dal
fin
cut
fOfl'
pre
par
atio
no
fba
cter
ia.
Fry
died
'at
2-30
p.m
,
Cau
dal
fin
rays
nak
edat
free
ex
trem
ity.
Cau
dal
fin
slig
htl
yaf
fect
ed.
Ep
ider
mis
eate
no
ffth
efr
eeex
term
ity
of
cau
dal
fin.
Cau
dal
fin
slig
htly
affe
cted
.
Ca
udal
fin
slig
htl
yaf
fect
ed.
~ o ll' o
13-1
1-38
64°
F.-
60
°F.
Co
lou
rd
ark
.ca
ud
alfi
nan
dca
ud
alpe
dunc
lese
riou
sly
affe
cted
.S
wim
min
gn
ear
sur
face
.D
ied
at11
a.m
,
Cau
dal
rays
expo
sed
hu
tn
ot
disi
nte
gra
ted
.
Co
lou
rd
ark
'lca
udal
rays
part
iall
yex
po
sed
.U
pp
erca
uda
llo
be
disi
nteg
rat
ed.
Die
dat
11am
.
Cau
dal
fin
rays
part
iall
yex
pose
d.
Cau
dal
fin
rays
part
ia
lly
expo
sed
.
*L
eng
this
up
toth
eba
seof
the
cau
dal
fin,
whi
cho
nac
coun
tof
its
dam
aged
cond
itio
nha
sn
ot
bee
nin
clud
edin
the
mes
ure
men
t.
14-1
1-38
15-1
1-38
16-1
1-38
17-1
1-38
18-1
1-38
19-1
1-38
64
°F.-
66
"F.
64°F.-66"~
64°
F.-
66
°F.
64°
F.-
66o
F.
64e
F.-
66
"F.
62°
F.-
6!O
F.r I
Die
dea
rly
inth
em
orn
ing.
Cau
dal
pe
dunc
lese
riou
sly
affe
cted
.L
ost
its
orie
ntat
ion.
Tu
rned
up
sid
edo
wn.
Die
dat
..12
a.m
.
Cau
dal
fin
rays
disi
nte
grat
ing.
Tu
rned
upsi
de
dow
nin
the
afte
r'n
oo
nan
dd
ied
at3
p.m
,
Cau
dal
fin
no
tsc
ratc
hed
.b
ut
rub
bed
agai
nst
the
caud
alfi
nof
rece
ntly
dea
dR
ain
bow
Tro
ut
Fry
at12
a.m
,
Adi
pose
fin
and
the
tis
sues
atth
eb
ase
ofth
isfi
nse
riou
sly
affe
cted
.
Th
efr
yd
ied
du
rin
gn
igh
t.
At
9a.
rn,
ino
cula
ted
onit
sca
ud
alfi
naf
ter
ith
adb
een
scra
tche
d.
Cau
dal
fin
and
cau
dal
pedn
nele
seri
ousl
yaf
fect
ed.
Att
emp
tsto
cure
the
dis
ease
fail
ed.
Die
din
the
mo
min
g,
V)~ -} t-
>.
~ b ~. ~ ~ "':t-
! "'"'c,,'~ ~ ~. l ~ <::
:l ..... <.N
"-l
<.N
374 Hamid Khan
The dead fry in all the cases sank to the bottom.
I mmum:ty of 7~uZigeno~,ts Species Six months old fry of Rohu (Labeo rohita H.Ik) and Morakha (Cirrhina
m~'igala t-I. B.), well-known indigenous food fish ofthe Punjab, were inoculated at the same time and in a similar manner as those of the RMnbow trout. But these fish were found to be totally immune to the disease.
Etiology and .Pathology Preparations made from Gourami (Plate XVIII, Fig. 6), and from Rain
bow trout fry (Plate XVIII, Fig. 5), show similar rod-shaped bacteria, which
are found in large numbers in the infected tissues. It is, therefore, apparent that the causative organism of the disease, both in Gonrami and Rainbow trout, is the same, as it is so uniformly present in the diseased tissue, l)avis (1937) 4 described the causative organism of fin-rot to be " a rod-shaped bacterium, which can usually be found in large numbers in the infected fins". Though no figures are given by him, it is, however obvious from the etiology and pathology of the fin-rot disease given by Davis, tha t the causative organism 5 of the disease in Go~rami and Rainbow trout is the same as causes the fin-rot. The infection usually starts on the outer margin of the fin and rapidly spreads to the underlying tissues. The fins which have been injured or scratched are the first to be attacked.
Davis (1937) is of the opinion tha t " in small fingerlings the pectoral fins usually are affected first, the dorsal fins being at tacked next, and the infection may spread eventually to the other fins, although they are rarely as badly affected ". In the Gonrami and the Rainbow trout fingerlings, in the present case, however, the sequence in the order of infection was different from that described by Davis. In almost all cases in the Gourami, caudal fins were affected before the dorsals and pectorals. I n the Rainbow t rout fry, too, the inoculated parts of the caudal fin developed the infection first.
According to Davis (1937), " In young fingerlings death usually occurs before the infection extends beyond the fins, so tha t the occurrence of lesions on the body is rare." The present investigations show tha t the disease in the case of Rainbow trout fry had spread with great rapidi ty to the under- lying tissues at the caudal peduncle where lesions were formed before the death occurred, while in Go~rami, the fingerlings died before the infection extended beyond the fins.
4 Davis , H . 8., " Care and Diseases of T r o u t , " Bureau of Pisheries, ~KS.A., ]nvestigational I~eport, 1937, No. 35, 58-60 .
5 Cul ture of czusa t ive org,~nism on s o m e of t h e c o m m o n l y u s e d L a b o r ~ t o r y m e d i~ a% L y M l p u r was nob successful.
SLudj: in Diseases o~ Pis ; : #7iz-Rot 375
C o n t r o l
Attempts to save the diseased Rainbow trout fry, under experiment, by giving them bath of copper sulphate solx~tion (1:5,000) for 2 minutes were not successful as the disease had spread to the underlying tissues. Control measures can only be effective in early stages of the disease before the bacteria have penetrated the tissues. D a v i s (1937) recom- mends " dipping the fish for 1 or 2 minutes in a 1-2,000 solutioll of copper su lpha te" . The copper sulphate solution of the strength recom- mended by Davis has been found to be too strong for young fry. I t has, however, been possible to t rea t the diseased Rainbow trot~t fry successfully by putt ing them in copper sulphate solution of 1-20,000 strength for 10 to 15 minutes. I t is impossible to cure fish in advanced stages of the disease and all such fish should be destroyed before any control measures are adopted as otherwise they will contaminate the water and form a permanent source of infection. Even healthy Rainbow trout fry, as the investigations have shown, when placed in contaminated water, develop the disease with great rapidity. I t is, therefore, very essential to disinfect thoroughIy all troughs, hatching and rearing trays, " live-cars " and " conditioning-cars "
before put t ing heal thy fry in them.
Rainbow trout fry have been found to suffer from the fin-rot at the hat- cheries, when they are overcrowded in a live-ear. I t has also been found tha t any injury, whether mechanical or otherwise, caused by external parasite, makes the fin more susceptible to the disease. I t has also been noticed tha t dirty, muddy rain water not only aggravates the disease, but has been found to be directly responsible for an outbreak of the disease among Rainbow trout fry. In the present case too, it seems, tha t t ransport of Gonrami fingerlings by canal, where water was to some extent dirty, aggravated the disease and the fry died very rapidly.
C o n c l u s i o n
Fin-rot has been found to be a serious disease of Rainbow trot~t finger- lings at the I-Iatche~y. The mortal i ty is very high and it has been observed tha t within one week from the o~tbreak of the disease thot~sands of fry have died. The present investigations indicate t ha t if once this disease enters a Gourami I~'arnl, and if due precautions are not taken, it is likely t o play a great havoc with the fry as well as with the adults. With due precautions it is possible to safeguard an outbreak of the disease. I t is exI~ected, there- fore, tha t the present investigations, which have established the suscepti- bility of Gourami to fin-rot, will have far-reaching effect on cnltivatioI1 of Oourami in inland waters in India.
376 Hamid Khan
Acknowledgments ~1y thanks are due to the Director of Fisheries, Madras, for providillg
me with facilities during my visit to Inland Fish Farms in Madras. I am indebted to ~ r . 2q. V. Joshi, Assistant Bacteriologist, Pusa hnperial Agricul- tural Research Institute, New Delhi, and Dr. 3/I. R. Z{adhok, Agricultural Bacteriologist, Lyallpur, for examination of the diseased fish and for prepara- tions of bacteria. I am thankful to Mr. S. ~ . Nasir, Punjab Agricultural Research Insti tute, Lya11pur, for the photographs and microphotographs appearing in this paper.
S~m~zry !. Study of fin-rot, a bacterial disease of the fins of fish, has been made
by inoculation of healthy Rainbow trout fry with the disease from diseased Gourami (Osphrorneq4~s god,fifthly Laegpgde) fingerlings.
2. The Rainbow trout fry infected with the disease died within 70-118 hours after inoculation and 50 to 55 hours after the first externally visible symptoms of the disease.
3. Preparations from the diseased Gourami and infected Rainbow trout fry show exactly similar causative organism, which is a rod-shaped bacterium, present in large number in the infected tissues.
4. Overcrowding, dirty and muddy water aggravates the disease.
5. Copper sulphate solution (1-20,000) bath for 10 to /5 minutes has been found to cure the fry in early stages of the disease. I t is impossible to cure fish in advanced stages of the disease, and all such fish should be destroyed before adopting aiay control measures.
6. F r y of indigenous fish such as Rohu (Labeo to%ire I-I.B.) and ~o rakha (Cirrhina, mri.ga, le tt.B.) have been found to be immune to fin-rot.
1881.89--Prlnted at The Bangalore Press, Mysore Road, Bangalore City, by G. Srinlvasa Rao, Sut~erinten dent, and Published by The Indian Academy of Sciences. Bang,dote
Dr. H~dd A'hcuz P-~vc. [)zd. ,4cad. SoL, B, voL X, PL X U I I I
Gourmxfi :fingerlings (OspTtrome'~.u,~ gou,r~.my h~c61?gde), showing fin-rot on e~udM, dorqat ~ncI anal fins
5 6
Microphotograph-of bacteria from caudal fila of Gourami-fingerling suffering from fin_ rut. • 1,200. (Oil immersion.) Acid fuch- sin.
Microphotograph o[ bacteria from caudal fin of Rainbow trout fry inoculated with fin- rot "disease. X 1,200. (Oil immersion.) G. Uiolct.
D~'. H~mid Kh~ Plot./Izc/. Acado s B, voL X, PI. . \ .~
|
8 9 t"
. . . . . . . . . . . . %.
F:G. I. Rainbow trout fry w:th /:ealthy caudal fin, FIGS. 2 to 4. Rainbow trout fry inoculated with fin-rot disease frmn dead
Gourami fry, showing fin-rot on their caudal lSns. Fins. S to 7. Rainbow trout fry put in contaminated water showing l]n-
rot o:l their caudal fi:~s. FIG, 8. Rainbow trout fry with fin-rot on its adipose fin. Fic. 9. Rainbow trout fr# with fin-rot on ira caudal fin,