Fish Diseases and Treatments

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PARASITE

Symptoms Diagnosis Treatment
Large white spots sprinkled like pretzel salt on body. Fish may be darting about and scratching on objects. A protozoan parasite Ichtyophthirius, commonly called Ick, most frequently the result of a sudden temperature change. "Scaleless" fish are more susceptable to illness. Malachite green solution for a minimum of 5 days, after which a water change should be performed. If tank has "scaleless" fish or small tetras, use 1/2 dose for a minimum of 7 days. NOTE: Although the spots disappear from the fish, do not stop treatment, this is normal due to the life cycle of this protozoan.
Tiny white or yellowish-white spots, may often appear like a dusting. Fish may be darting about and scratching on objects A dinogflagellate parasite called Oodinium. Malachite green solution or acriflavin for a minimum of 5 days. A combination remedy containing both Malachite and furazone will be more effective, as well as help treat any bacterial infections that result from the infestion.
Similar to Oodinium but less translucent, generally starts on dorsal area above head, affected fish are generally cichlids or livebearers. A protozoan parasite Costia. The most effective treatment is a remedy containing a combination of malachite green and dylox. If such a remedy is not found, a malachite-formalin complex can be used.
Emaciation, erratic swimming behavior, and loss of color, the loss of the red stripe on a neon or cardinal tetra is a giveaway. Affected fish are generally small tetras, but can include danios and barbs. A protozoan parasite leading to the condition commonly called Neon Tetra Disease. Treatment is difficult, a remedy containing nalagram has had the best results. A furazone-based treatment may be affective as well.
Small holes appearing particularly in the head region, affected fish tend to be cichlids, particularly discus and oscars. A protozoan parasite Hexamita, leads to the condition commonly called Hole-in-the-Head Disease. Usually the result of overcrowding, poor water quality, or overuse of feeder fish (in the case of large cichlids). So first remedy the cause, then treat with metronidazole added to the water (it is hard to find without a prescription, but it is available over the counter). NOTE: The scars may not heal completely after treatment.
Large parasite found most often on goldfish, may be 3/4" long and found attached to the body of the fish. A crustacean parasite Lernia, commonly called Anchor Worm. The organophosphate dylox (or a similar compound) to the water (care must be taken with this medication!), and manually remove the adult parasites from the affected fish.
Fish has translucent crab-like organisms measuring 1/2" in length scurrying about its body. Ponds are the most common sites for outbreaks. A crustacean parasite called Argulus, commonly called Anchor Worm The organophosphate dylox (or a similar compound) to the water (care must be taken with this medication!). Potassium permanganate may be used as an alternative treatment

Fungus

Symptoms	Diagnosis	Treatment
Greyish-brown cottony tuftftlike material covering body. May occur on a fish after injury.	True Fungus, normally caused by *Saprolegnia*.	If entire tank is affected, treat using a methylene blue solution or other proprietary TRUE fungus medication. If only one or few fish are afflicted, remove the fish and treat affected area directly with a methylene blue or malachite green solution, being careful not to let solution get into gills.
Thick greyish-white marks around mouth or body of fish	Mouth or Body Fungus, actually a bacterial disease usually caused by the bacterium Flexibacter.	A proprietary antibiotic containing erythromycin .

Bacteria

Symptoms	Diagnosis	Treatment
Red spots or streaks on body or fins of fish.	Septicemia and Ulcer Disease caused by bacteria including *Pseudomonas, Aeromonas,* and Vibrio.	If entire tank is affected, treat using a gram-negative proprietary antibiotic. It is recommended to feed the fish a medicated fish food containg an antibiotic, as the bacteria is most likely internalized as well.
Torn, ragged or stumpy fins, often edged in white.	Finrot usually caused by *Pseudomonas, Aeromonas,*	Treat using a gram-negative proprietary antibiotic. Placing a dab of methylene blue or malachite green directly on affected fins may help disinfect the areas and prevent secondary infections.
Bloated body, scales portrude from body, loss of appetite. Generally affects goldfish or african cichlids	Dropsy (goldfish) or Malawi Bloat (african cichlids).	The definite cause for this disease is unknown, so medication is difficult. A broad spectrum proprietary antibiotic coupled with the best possible water quality and food offers the best chance at treating these illnesses.

Diagnosing fish disease

It is not possible to diagnose fish disease purely on the basis of behaviour or physical changes. These "clinical signs" that something is wrong can be useful as pointers to possible problems. However, many of these clinical signs can be caused by more than one disease condition, which is why further examination and tests are essential to make a definite diagnosis. Without any examination or tests, it is simply guesswork as to what is wrong!

The table below indicates some of the most common disease signs, and details further steps to take to help confirm a diagnosis.

Clinical Signs	Possible Causes
The sudden death of many fish over a short period of time with few preceding symptoms. Surviving fish hang around the water surface / stay on the bottom and may lose equilibrium. They are lethargic and don't eat.	1) Acute poisoning. Water should be tested for core parameters and fish examined for signs of severe parasite or bacterial infection. If possible, post mortem recently dead fish. If these are negative carry out a 75% or more water change on the presumption of some (as yet, unknown) toxin. Send water sample away for toxicology testing. 2) Low dissolved oxygen levels. Measure levels in pond/ filter early in morning when DO levels at at their lowest 3) Peracute bacterial disease. Diagnosis would require post mortem and aseptic bacterial sampling of organs
Fish rub against solid objects and "flash" when they turn to rub their sides giving a flash of silver colour as their undercarriage is exposed. They may also leap out the water.	This indicates some form of irritation of either the skin or gills. 1) This could be caused by raised levels of ammonia, nitrite or high/low pH. Widely fluctuating diurnal shifts in pH can also cause irritation. Check all water parameters 2) Irritation can also be caused by ectoparasites such as flukes, Trichodina, white-spot etc on the skin or gills. do a skin scrape of two to three fish. Examine the gills.
Fish swim normally but appear to be breathing heavily. (This can be judged by operculum movements). Fish appear to be gasping, they may crowd water inlets	1) Hypoxia. Dissolved oxygen levels may be low, test levels early in morning. 2) Poor water quality causing gill hyperplasia, excess mucus production or nitrite toxicity. Check ammonia,nitrite and pH levels. Check that pond and filters are clean 3) It could indicate the early stages of gill disease If the condition persists it is important to examine 2-3 fish for gill parasites or gill disease. 4) Gill parasites. Take skin and gill scrapes 5) Anaemia. Gills look pale
Individual fish stay apart from others. Breathing is normal. They may refuse food. They may have "cloudy" or grey areas on the skin. There are no other physical signs.	Lethargy and inappetence are common symptoms of many diseases, so further investigation is essential 1) Fish may be suffering from a parasite problem. Take a skin and gill scrape. Examine the gills. 2) There could be internal disease problems 3) Early stage of systemic bacterial infection. Isolate and observe 4) Test water parameters
Several fish are lethargic. Fish are not eating or eating very little. Fish are skittish and shy. Some fish may have split or ragged fins	Lethargy and inappetence are common symptoms of many diseases, so further investigation is essential 1) Poor watery quality. Check ammonia,nitrite, and pH 2) High levels of organic pollution 3) Ectoparasite infection Check 2-3 fish for parasites and gill problems 4) Early stage of bacterial disease. Examine fish for lesions, inflammation and ulceration.
Overproduction of gill and/or skin mucus. Grey slime/ trailing mucus. May be accompanied by rubbing/flashing, heavy 'breathing' and/or lethargy.	1) Ectoparasites. Take skin and gill scrapes 2) Poor water quality. Test core parameters
Skin lesions or ulcers Reddening or inflammation on the body or fins. Raised scales. Localised swelling. Open wounds or lesions that do not heal within a day or two	1) Physical damage. This will normally present as a 'clean' lesion with little inflammation. Usually heals within days. Always a risk of secondary infection. 2) Local tissue irritation caused by ectoparasite infection. Take skin and gill scrape 3) Bacterial disease 4) Water quality problem. Test core parameters 5) High levels of organic pollution. Check pond and filters for decomposing solids
Focal red or white lesions on the body	Larger ectoparasites such as lice, leeches or anchor worms. These parasites are normally visible with a close examination
Fin rot Frayed, split or ragged fins. Possibly with whitish edge and some reddening of the fins	1) Bacterial infection 2) Ectoparasite infection. Take skin and gill scrape 3) Poor environmental conditions. Test core parameters and check that the Pond and filters are clean 4) Physical damage 5) Over crowding 6) Fungus infection 7) Columnaris infection (mouth fungus/cotton wool disease)
Fish has swollen abdomen (dropsy). Possibly raised scales and some reddening on the body or fins. They may possibly exhibit pop-eye (exophthalmos)	1) Viral infection. 2) systemic bacterial infections: leading to 'dropsy' (build up of fluid in the abdomen. Can be differentiated from tumour by shape, symmetry and feel (feels soft and fluidy) 3) Neoplasm (tumour). Can usually be determined by size, shape (usually asymmetric) and palpation (feeling - usually hard) 4) Heart or kidney disease. Can only be diagnosed by post mortem 5) Internal parasites 6) Genetic disorder 7) Intestinal blockage. Only established at post mortem
Fish have respiratory problems shown by gasping or laboured gill movements. Gill examination shows areas of necrosis (dead tissue), mottled appearance, heavy mucus.	1) Bacterial gill disease 2) Viral infection 3) Branchiomyces (gill rot) 4) Parasites on the gills :Take biopsy/ scrape for microscopic examination
Tiny white spots over the skin and fins, as though fish has been sprinkled with salt. Usually with thickened mucus	Ichthyophthirius (white spot).
White or or discoloured 'cotton-wool' patches on the skin or fins. Often accompanied by inflammation and skin erosion	1)fungus infection 2) Columnaris infection (mouth fungus/cotton wool disease). Take sample for microscopic examination which would show typical long 'gliding' bacteria (Flexibacter sp).
Swellings on the skin	1) Parasitic cysts. 2) Physical damage. Examine fish and observe 3) Bacterial infection. Usually accompanied by inflammation and raised scales. Examine fish for Raised sca;es and or inflamation , 4) Internal tumours
Growths on skin / fins	Tumours or viral infections such as; 1) 'carp pox', which resembles melted wax poured over the fins or skin 2) papillomas, 'warty' types of growths, can be quite large, smooth or cauliflower-shaped, white, red or pink 3) lymphocystis, various sized, white to pink masses on the skin and/or gills. Diagnosis is by microscopic examination of 'wet mount' taken from the lesion. * There are no treatments for these growths. They are usually benign and often self-resolving. There is always the risk of secondary bacterial infection
Corneal Opacity (cloudy eye)	1) Physical damage 2) Nutritional deficiencies 3) Poor water quality 4) Bacterial infection
Skeletal deformities / kinked spine	1) Electrical shock. Faulty electrics or lightening strike 2) Use of organoposphates 3) Nutritional imbalance 4) Genetic abnormalities 5) Muscular damage / physical damage 6) Toxins Unless there is an obvious known problem, it is difficult to establish the cause. A radiograph (sort of x-ray) would assist for skeletal problems
Loss of equilibrium with fish unable to stay upright. Fish may be able to maintain position when swimming, but turn over when they stop swimming.	1) Disease/ swim bladder disorder caused by viral or bacterial infection, constipation (mainly fancy goldfish) or other organ disease. 2) Internal organ disease, i.e. kidney / intestinal disease or blockage. Usually only established at post mortem
Lethargy, weight loss, chronic mortality. There may be worms protruding from anus	1) internal parasites (endoparasites). Requires blood sample, wet mounts from dissected tissues and wet mounts of faecal sample