I. Copepod parasites

Argulus n 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

Lernea –Slender copepods with anchor attachment (5- 22mm) –anchor causes tissue damage –Secondary infection

Lernea –Easily identified –Primarily warmwater fish –Egg sacs are very obvious

Ergasilus –External –Small ( mm) –Gill parasite –Many fish species –Only females on fish –Claw like claspers –1 million eggs year –live 1 year

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

II. Trematode parasites

Gyrodactylus –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

Dactylogyrus –Monogenetic –Lay eggs in water (not as explosive as Gyro) –4 eyespots –1 pair hooks, 16 hooklets

Dactylogyrus –Primarily a gill parasite –So cause gill damage and symptoms can be mistaken for O2 problem or other gill infections –Primarily warmwater, especially cyprinids

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

Digenetic 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 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. Protozoa

I. 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 o life cycle only 3-4 days »Only free swimming vulnerable

I. multifilis

Chilodonella –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

Chilodonella

Ambiphrya –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

Epistylis –Stalked ciliates –Usually on skin but also gills –Also eggs (fuzzy so can confuse with fungus) –Trout, walleyes, catfish, others –Signs »flashing »secondary infection

Epistylis

Trichodina –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 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

Ichtyobodo –Costia, external –Flagellate, small, pearshaped, flickering flame –A couple species –Trout, salmon, ww fish especially bad on trout fingerlings and catfish

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

Henneguya –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 –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 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

Plistophora –Internal –Several species –Small (3-6 microns) beanshaped –Trout gills, golden shiner ovaries (reduces fecundity) –No control

Plistophora

Cryptobia 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 disease

Fungal 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

Saprolegnia

V. Bacterial disease

Furunculosis –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

Furunculosis

Pseudomonus –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 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 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 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 Disease –Above 56 o becomes more of a problem –Fish can't get rid of CO 2 and ammonia or get O 2 –Often secondary fungal infection –Signs »lethargic, off food, pipe, "ride high" »whitened gill tips, excess mucous –Worse in fingerlings

Flexibacter columnaris –external and internal –Columnaris disease –Through skin and gills, especially if scratched –Seldom a problem below 55 o F worse at 65 o F –Primarily salmonids and catfish –Signs »grayish white body lesions with bright yellow slime »common on head and mouth »internal also

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

Tuberculosis –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

Tuberculosis

Vibrio 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 salmoninarium –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 diseases

Infectious Pancreatic 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 Septicemia –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 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 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

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

Lymphocystis