DISEASE AGENT TYPE SYNDROME MEASURES
Viral nervous
necrosis (VNN)
Lates calcarifer
encephalitis
virus (LcEV)
– a
betanodavirus
Virus
Pale or dark colouration; erratic swimming
behaviour; spiral swimming; bloating;
'fainting'; extensive vacuolation of the brain
& spinal cord; generally encountered during
hatchery phase
Screening of
broodstock; low
larval rearing
densities; optimal
larval nutrition;
improved broodstock
nutrition; improved
hatchery hygiene
Lymphocystis
Lymphocystis
virus Virus
Wart-like growths on skin & fins; generally
only fatal if infection severe & associated
with very poor environmental conditions
Removal of infected
fish; improved
environment
Vibriosis Vibrio harveyi;
Vibrio spp. Bacteria
Marine fish with darkening; lethargy;
anorexia; reddened ulcerations on body;
reddened abdominal fluid; associated with
nursery systems, poor environment & skin
trauma
Improved
environment;
antibiotic treatment
Bacterial
haemorrhagic
septicaemia
Aeromonas
hydrophila;
AAeromonas
sobria;
Aeromonas caviae;
Aeromonas spp.;
Pseudomonas sp.
Bacteria
Freshwater fish with irregular reddened skin
ulcerations; lethargy; anorexia; reddened
abdominal fluid; pale gills; associated with
poor environment & skin trauma
Improved
environment;
antibiotic treatment
Integumentary
bacteriosis
Aeromonas
sobria;
Aeromonas
hydrophila; Vibrio
harveyi; Vibrio
alginolyticus
Bacteria
Irregular reddened skin ulcerations; loss of
scales; associated with poor environment &
skin trauma
Improved
environment;
increased water
exchange
Streptococcosis Streptococcus iniae Bacterium
Darkened fish; anorexia; pale gills;
reddened abdominal fluid; reddened
abdominal organs & inner wall
Antibiotic treatment;
vaccination
FAO Fisheries and Aquaculture Department
Columnaris
disease
Flavobacterium
columnare;
Flavobacterium
johnsoniae; &
Flavobacterium
sp. (gliding
forms) in
freshwater
Tenacibaculum
marinimum in
seawater
Bacteria
Pale skin patches on dorsal surface behind
dorsal fin & on caudal peduncle; lethargy;
most commonly occurs in nursery phase; in
older juveniles a mouth form with erosion of
skin around upper & lower jaws has been
seen; associated with overstocking, tank
rearing, poor hygiene & skin trauma
Treatment in
potassium
permanganate or
copper baths may
help in early disease;
antibiotic treatment
Bacterial gill
disease
Various
bacteria,
Flavobacterium
spp., Cytophaga
spp.
Bacteria
Swimming at water surface; gulping; rapid
opercular movement; excess mucus on gills;
white patches on gills; most commonly
occurs in nursery phase
Improve water
quality; treatment
with salinity reversal,
potassium
permanganate or
quaternary
ammonium baths;
increase water
exchange; reduce
stocking density
Bacterial
peritonitis
Various
Gramnegative
&
Gram-positive
bacteria
including
Vibrio harveyi &
Aeromonas
hydrophila
Bacteria
Darkened fish; lethargy; swollen abdomen;
adhesions & bad smelling fluid in abdomen;
abdominal fistulas; more common in
recirculation systems
Cull affected fish;
antibiotic treatment
Bacterial enteritis
Various
Gramnegative
bacteria
Bacteria
Acute disease in intensive larval rearing
systems; anorexia; pin heads; darkened fish
& death
Cull affected larval
batch
Fin and tail rot
Aeromonas spp.;
Pseudomonas
spp.; Vibrio
spp.;
Flavobacterium
spp.; Cytophaga
spp.
Bacteria
Erosion of soft tissue in fins and tail; may
extend to involve entire tail & caudal
peduncle
Improve
environment; reduce
stocking density
Epitheliocystis
Epitheliocystis
organism – a
Chlamydia
Bacterium
Swimming at water surface; rapid opercular
movements; disease rare but seen in marine
fish & in recirculation systems
None known
White spot
Ichthyophthirius
multifiliis in
freshwater
Cryptocaryon
irritans in
marine
Protozoa
'Flashing'; rubbing skin on surfaces;
anorexia; swimming at water surface; white
spots on skin & fins
Treatment with
salinity reversal,
formalin baths or
combinations;
treatment in copper
bath for marine fish
Chilodonelliasis
Chilodonella
spp.; Protozoa
Swimming at water surface; rapid opercula
movement; flared opercula; seen in poor
Treatment with salt,
formalin or
potassium
FAO Fisheries and Aquaculture Department
Chilodonelliasis spp.;
Chilodonella
hexasticha
Protozoa environmental conditions & in weakened
fish
potassium
permanganate bath
or combinations
Trichodiniasis Trichodina
complex spp. Protozoa
Swimming at water surface; rapid opercular
movements; excess gill mucus; typically
follows cold water temperatures, high
organic loads & high stocking densities
Increase water
exchange; treatment
with salt or formalin
bath
Ichthyobodosis
(costiasis)
Ichthyobodo
necator Protozoa
'Flashing'; rubbing skin on surfaces; opaque
patches on skin; raised scales; swimming at
water surface; rapid opercular movements;
flared opercula
Treatment with
salinity reversal;
formalin or
potassium
permanganate bath
Piscinoodiniasis Piscinoodinium
sp. Protozoa
Found in freshwater: In young fish opaque
patches or a greenish discolouration of the
skin; patches of skin lifting o