I. Copepod I. Copepod parasitesparasites

ArgulusArgulus External, fish lice

– primarily a pond problem– visible, flat, move about– 2 sucking disks for attachment– Pierce skin with mouthpiece

and feed on blood. – Large number vs. small

number– Secondary infections occur

LerneaLernea

– Slender copepods with anchor attachment (5-22mm)

– anchor causes tissue damage

– Secondary infection

LerneaLernea

– Easily identified– Primarily warmwater

fish– Egg sacs are very

obvious

ErgasilusErgasilus

– External– Small (1.5 - 2.5 mm)– Gill parasite– Many fish species

– Only females on fish– Claw like claspers– 1 million eggs year– live 1 year

Actheres ambloplitisActheres ambloplitis

– External– Common on catfish– Gill parasite– Attach by leg like structures– Egg sacs– Especially bad on larval fish

II. Trematode II. Trematode parasitesparasites

GyrodactylusGyrodactylus

– External, visible– Monogenetic (complete life cycle on fish)– Live young - move readily– No eye spots– Haptor with 1 large pair of hooks and 16 hooklets– Skin irritation but also on gills and fins– Signs are listlessness, frayed fins, flashing, fungus– Heaviest in winter and spring

DactylogyrusDactylogyrus– Monogenetic– Lay eggs in water (not as

explosive as Gyro)– 4 eyespots– 1 pair hooks, 16 hooklets

DactylogyrusDactylogyrus

– Primarily a gill parasite– So cause gill damage and

symptoms can be mistaken for O2 problem or other gill infections

– Primarily warmwater, especially cyprinids

CleidodicusCleidodicus

– External, monogentic– Eyespots– 4 large anchor hooks– Lay eggs– On gills is problem– Symptoms looks like O2 problem– Warmwater fish, especially catfish

Digenetic trematodesDigenetic trematodes

– Quite a number are problems– Some internal, some external– Require more than 1 animal host– Sanquinicola in salmonids

» blood fluke» snails are intermediates

Digenetic trematodesDigenetic trematodes

– Various types of yellow and black grubs» common in wild but in ponds also» aesthetic problem only» don't know why not in text» snail - fish - bird cycle

III. ProtozoaIII. Protozoa

I. multifilisI. multifilis– Large ciliated protozoan– Primarily ww fishes but some cw– White color with large horseshoe shaped nucleus– Flash, twitch, flag– Heavily infested fish are lethargic– Skin, gills, fins - penetrate skin so not exactly external– Can be explosive since 1,000 or more from one– At 70-75o life cycle only 3-4 days

» Only free swimming vulnerable

I. multifilisI. multifilis

ChilodonellaChilodonella– External– Numerous species– Small, oval, colorless, ciliate (faint bands)– Skin, fins, gills– Both warm and cold but primarily warm and under

crowded cond.– Signs -- listless, off feed, flashing, lie on side– Easy to control

ChilodonellaChilodonella

AmbiphryaAmbiphrya– Several species– Small urn-shaped ciliate– Ring of cilia at top end and band of cilia in middle– Skin, gills, fins of salmonids and warm water fish -

particularly bad on bass and catfish - young– Usually harmless, but if a lot the scopola (attachment

organism) smothers gills. – Signs -- piping, may look like bacterial gill disease,

redden skin & gills, listless– Easy to control at this time

EpistylisEpistylis– Stalked ciliates– Usually on skin but also

gills– Also eggs (fuzzy so can

confuse with fungus)– Trout, walleyes, catfish,

others– Signs

» flashing» secondary infection

EpistylisEpistylis

TrichodinaTrichodina– External– Ciliate - many species– Saucer shaped, rows of

cilia, especially on margin. – Skin, fins, gills, activity

» Signs -- flashing, tattered appearance of fins, white irregular blotches

» secondary bacterial problems

Hexamita salmonisHexamita salmonis– Octomitus, internal– Tiny flagellate– Colorless (must stain), pearshaped - 8 flagella– Salmon and trout intestines– Irritate gut lining, irregular swimming, yellow intestinal

fluid– Some question its status as a pathogen.– Apparently more of a problem when non-prepared foods

fed

IchtyobodoIchtyobodo

– Costia, external– Flagellate, small,

pearshaped, flickering flame

– A couple species– Trout, salmon, ww fish

especially bad on trout fingerlings and catfish

IchtyobodoIchtyobodo

– Signs» light bluish - grayish film» lose appetite» flash» crowd bottom - listless» have to examine

microscopically

HenneguyaHenneguya

– Internal– From many species warm and cold water– A myxosporidean– Encysts in tissue– Muscle damage, but some stages on gills so– No control

Ceratomyxa shasta Ceratomyxa shasta – Internal myxosporidian

– Salmonids

– Has caused many epizootics of 100% mortality

– Intestine and gall bladder, spleen, liver, and kidney

– Signs

» vent area swelling

» distended abdomen

» early are listless, off food, seek slack water

» fish may darken

– No treatment - transmission method unknown

Myxosoma cerebralisMyxosoma cerebralis– Internal myxosporidian protozoan– Twisted spines and deformed backs– Salmonids– Whirling or tail chasing is a sign "called whirling

disease"– Survivors often deformed and have "Blacktail" (loss of

chromatophore control)– No known control method except prevention– Really a problem in young fish

PlistophoraPlistophora

– Internal– Several species– Small (3-6 microns)

beanshaped– Trout gills, golden

shiner ovaries (reduces fecundity)

– No control

PlistophoraPlistophora

Cryptobia borreliCryptobia borreli

– Flagellate– Variety of fishes including salmonids– A blood parasite, affects kidney function– Signs

» anemic» popeye (exophthalmic)» fluid in body cavity

– No treatment

IV. Fungal diseaseIV. Fungal disease

Fungal diseaseFungal disease– Pervasive– Numerous species including Saprolegnia– Fish and eggs– Warm, cool, cold– Appears as a white cottony growth on eggs on fish is white

to brownish patches on various body areas– Any damage to body surface can open way, spawning,

netting, handling– Control by sanitation, or chemicals, for others no control– Often prophylactic type treatment of eggs

SaprolegniaSaprolegnia

V. Bacterial diseaseV. Bacterial disease

FurunculosisFurunculosis– Aeromonas salmonicida -- Salmonids– Cause muscle lesions– Can enter through scratch or digestive tract– Bacteria produces a toxin– Signs

» blisters or patches - bluish - red or purple» hemorrhages at fin bases or frayed dorsal fins» acute lesions

– Short incubation

FurunculosisFurunculosis

PseudomonusPseudomonus– Also called fin rot

– Signs

» superficial grayish - red skin ulcers

» dropsy

» popeye

» inflamed fins

– Many fishes affected - frogs also

– Much different than fin rot

– Warm and cold

– Variety of symptoms

Cytophaga psychrophiliaCytophaga psychrophilia

– external– Usually called peduncle disease– A low water temp. disease– Signs

» darkening» lesions on peduncle or near pectoral fins

– Worst on young fish– Can result in total erosion of caudal area– Primarily a problem in 40-50oF range

Yersinia rucheriYersinia rucheri– Causes enteric redmouth disease in salmonids– Inflammation and erosion of jaws and palate– May kill more RBT than any other bacterial agent– Signs

» black, popeye» lethargic, drift at surface» mouth and tongue inflamed, underbelly with spotty hemorrhages» dead fish with dropsy» fin sockets hemorrhaged, in heavily infected fish - gill bleeding

– Especially a problem in intermountain west and still growing– Worst in hot summer months

Bacterial Gill DiseaseBacterial Gill Disease

– external– Called GD often– Salmonids and warm water (but primarily

salmonid)– Superficial infection of gill epithelium– By an undecided bacteria, probably related to

columnaris disease causative agent

Bacterial Gill DiseaseBacterial Gill Disease

– Above 56o becomes more of a problem

– Fish can't get rid of CO2 and ammonia or get O2

– Often secondary fungal infection– Signs

» lethargic, off food, pipe, "ride high"» whitened gill tips, excess mucous

– Worse in fingerlings

Flexibacter columnarisFlexibacter columnaris

– external and internal

– Columnaris disease

– Through skin and gills, especially if scratched

– Seldom a problem below 55oF worse at 65oF

– Primarily salmonids and catfish

– Signs

» grayish white body lesions with bright yellow slime

» common on head and mouth

» internal also

Hemophilus piscium Hemophilus piscium

– internal– Ulcer disease– Ulcers or sores on surface of fish and work inward– Resembles furunculosis but opposite sores work

in but in furunculosis work out– Circular sores– Salmonids primarily

TuberculosisTuberculosis

– Related to human tuberculosis bacterium– Salmonids– Almost no problem now since don't feed fish

viscera products– External and internal lesions

– kidney, spleen, liver, digestive tract

TuberculosisTuberculosis

Vibrio anguillarumVibrio anguillarum

– internal– Called Vibriosis– Many fish– Primarily a problem of marine cultured fish– Signs

» off feed» lethargic» erratic swimming, spinning» bloody discharge from vent» internal

Renibacterium Renibacterium salmoninariumsalmoninarium

– internal– Causes kidney disease– Salmonid problem– Kidney lesions but can develop into

musculature fluid in body cavity, dropsy– Really a lot not known about this and is a

real problem

VI. Viral diseasesVI. Viral diseases

Infectious Pancreatic Infectious Pancreatic Necrosis (IPN)Necrosis (IPN)

– Salmonids, NA & Europe– High fingerling loss– Over 6 in. are carriers– Signs

» death rate up for healthy looking fish in fact some of best looking die first

» some spiral and roll

» tail chasing, darkening, popeye, dropsy

» internal also

– A small pathogen– June and July worst months

Viral Hemorrhagic Viral Hemorrhagic SepticemiaSepticemia

– Primarily Rainbow Trout– Not bad on fry or adults - middles ones worse– Not egg transmissible but– Signs

» color, popeye» hemorrhage at fin bases» lethargic, seek edges» internal also

– Late winter, early spring

Infectious Hemapoietic Infectious Hemapoietic Necrosis (IHN)Necrosis (IHN)

– Rainbows and some other salmonids– Not egg transmissible but a lot not known– Ovarian fluid can do it– Signs

» flagging» dark, lethargic, popeye» hemorrhaging tissue near vent and fins» pale gills» internal also

– April to June

Channel Catfish Viral Channel Catfish Viral Disease Disease

– CCVD, CCV– Signs

» when temperature reaches 70oF sudden increase in death» spiralling or swimming abnormally» convulsions» just before death at surface with tail down» fin base hemorrhage» internal also

– Often obscured by columnaris– Appears to be host specific for catfish

LymphocystisLymphocystis

– Many fish but walleyes and centrarchids worse– Mostly aesthetic, chronic– Abnormal growth of connective tissue - wart like

LymphocystisLymphocystis