Fish Health Management
(Part 1)

by Dr. Arthur Lembke

Before I start this article, I would like to thank the MAKC for choosing me to attend the course on Fish Health Management this year. The course was offered by Dr. John Gratzek at the University of Georgia. The course lasted for 3 and 1/2 days and included classroom and laboratory studies. There was much to learn from this highly noted expert on fish health and I was glad to have the experience of studying with such a learned individual. If at all possible, I would highly recommend this course to all MAKC members. As a way to say thank you to the MAKC, I would like to write several articles, reviewing the information given to me by Dr. Gratzek. I make no claims as to the accuracy of the information. In fact, some information presented I still question, but that is what made the course so interesting. There was ample time during and after class to discuss these differences. The class was also a great place to meet others and share information. There were several dealers and distributors, veterinarians, hobbyists, someone from Disney, someone from Sea World, and even an airplane pilot.
The first day of the Fish Health Management course, fish basics were presented so we could better understand the disease process. Gill function was a good start. Gills function to take in oxygen and put out carbon dioxide. Gills excrete 70% of the ammonia of the fish and the kidney excretes the other 30%. The gills are responsible for osmoregulation which controls the uptake of chloride, the excretion of sodium, the balance of water in the fish, and the balance of electrolytes. Stress on a fish can affect osmoregulation in the following ways:


Stress can be reduced by maintaining a salt concentration of 0.3% in the pond water, and possibly by using corticosteroid injections in severe cases.
Next, a short review of filtration was presented. Mechanical filters were discussed. Three types were mentioned, including sediment chambers, entrapment (i.e. sand or gravel filters), and foam fractionators. It was agreed that foam fractionating does not work as well for fresh water application. The process by which filtration breaks down ammonia into nitrite and then nitrate was quickly reviewed and it was stated that this process gives off hydrogen ions which brings the pH down unless buffering capacity was increased in the pond. It was also stated that salt in the pond does not seem to alter or slow down the development of the ammonia cycle.
To help a new system start up better, with less stress on the fish, the following suggestions were made: When adding new water to the pond, Dr, Gratzek stated that chlorine could be taken out of the water by aeration, sunlight, activated carbon, or sodium thiosulfate. He seemed to prefer sodium thiosulfate because it was cheap and seemed to be very safe with fish. Chloramine was said to be removed by activated carbon or sodium thiosulfate. However, sodium thiosulfate removes the chlorine of the chloramine molecule but leaves the ammonia behind. The remaining ammonia would have to be taken up by the filters or removed by ammonia neutralizers (i.e. Zeolite, Amquel).
The next topic Dr. Gratzek presented was water chemistry and quality. This will be the subject of an upcoming article.

Fish Health Management
(Part 2)


by Dr. Arthur Lembke

The next part of the lectures on Fish Health Management presented by Dr. John Gratzek at the University of Georgia covered water chemistry and quality. The information was more detailed because this subject has a lot to do with the management of fish health.
The first water parameter that was discussed was oxygen. Fish need oxygen for proper body function and filter bacteria need oxygen to carry out the nitrification process. The following situations affect the oxygen levels in water:


pH

was defined as the concentration of hydrogen ions (H+) in the water in relation to the OH- ions. High pH (above 7.5) will make ammonia more toxic to fish. This is because the normal balance of ammonia (toxic) to ammonium (less toxic) molecules in the pond is pushed toward the ammonia end at a higher pH. Therefore, optimal pH of a pond would be 7.2 to 7.4 to reduce ammonia toxicity. To lower the pH, it was suggested the alkalinity be lowered first by water softeners or reverse osmosis. Then monobasic sodium phosphate can be slowly added to lower the pH. Peat moss in the filter may also help to lower pH. To raise the pH, one can use commercial buffers, water changes, oyster shell, or sodium bicarbonate. The class tested the use of sodium bicarbonate and the highest pH reached was 8.4, at which point further additions of sodium bicarbonate did not change the pH.

Hardness

measures the amount of calcium carbonate in the water. Soft water is 0 to 75ppm, moderately hard water is 75 to 150ppm, hard water is 150 to 300ppm, and very hard water is 330+ ppm. Ideal for koi ponds seems to be in the moderately hard range. Harder water generally means high alkalinity, higher buffer, and increased resistance to pH changes.

Alkalinity

is the concentration of carbonate in the water. The higher the alkalinity, the less pH fluctuations. In water with low alkalinity, the filtering process will drive the pH down. Keep alkalinity above 80ppm.

Ammonia

was discussed next. Ammonia is toxic to fish because it causes less oxygen to be taken up by the gills and it interferes with osmoregulation. Gills become irritated and the fish surface in the pond. As mentioned earlier, the ammonia is more toxic at higher pH, therefore if ammonia is present, as in start_up, it is important to maintain pH below 7.5. Ammonia is controlled by:

Nitrite

is the next component in the filter nitrification process. Nitrite is toxic as well, and can cause the fish to be lethargic, have flared gill plates, and dark blood. If fish die of nitrite toxicity, they die with their mouth open. Methods of lowering nitrite include:

Nitrate

is the end product of nitrification and is not as toxic to fish unless present in very high concentrations. Nitrate is reduced by plants and algae. It can also be reduced by doing water changes and reducing fish load.
Hydrogen sulfide was mentioned as a toxic concern in water. It comes from anaerobic decomposition in the pond. This can be avoided by cleaning filters and removing mulm from the pond.
Organics include proteins, amino acids, and carbohydrates given off by the fish as waste. Organics will increase bacteria growth, increase protozoan growth, and inhibit fish appetite, growth, and immunity. Organics can be reduced by decreasing food, increasing filtration, decreasing fish load, and water changes.
Other water pollutants include chlorine, cyanide, detergents, fertilizers, pesticides, and thermal pollution.
The rest of the course covered in depth disease information and laboratory diagnosis of disease. This will be covered in upcoming articles.

Fish Health Management
(Part 3)

by Dr. Arthur Lembke

The rest of the Fish Health Management course presented by Dr. Gratzek covered diseases in general as well as specific disease information. Laboratory dissections were also done each day to learn methods of preparing slides for microscopic diagnosis and to see various diseases.
It requires the right combination of three elements for a fish to get a disease. These elements are the host, the pathogen, and the environment. The most important thing to learn from this information is that you can have a fish in the presence of the pathogen, but if the environment is good, the fish will not become diseased. We tested this in the lab by putting water samples on agar plates that grew only Aeromonas. We found that Aeromonas is always found in the water, even with healthy fish.
General disease information was given to include the following:

The first group of diseases discussed were the non_infectious diseases. These are basically nutritional problems. Nutritional problems arise from: 1. spoiled stored food 2. pellet size too large for fish to eat 3. not enough food 4. not enough Vitamin C 5. not enough Vitamin E Therefore, feed as many times a day as possible with small amounts of food and put variety in the diet. Signs of nutritional deficiency include: 1. decreased appetite 2. ascites 3. lethargy 4. poor growth 5. decreased color 6. dark skin 7. deformities 8. anemic 9. fatty liver 10. blindness/cataract Signs of poor nutrition include: 1. decreased disease resistance 2. excitable 3. increased slime 4. poor appetite
Specific diseases will be discussed in an upcoming article.

Fish Health Management
(Part 4)

by Dr. Arthur Lembke

The rest and majority of the Fish Health Management lectures presented by Dr. Gratzek at the University of Georgia were spent on studying specific diseases, including diagnosis and microscopic study. Many diseases were discussed, including some which do not pertain to koi or goldfish. To simplify a complex subject, I will review only those diseases that we would encounter as koi hobbyists.
The first, and probably, the most important of the diseases for koi keepers are parasites. It is rare to find a fish that is parasite free, as we know from doing mucous scrapes of healthy fish. Parasites may be passed through water, therefore, it is important to remove dead fish from ponds immediately.
Diagnosis of parasites includes:


Clinical signs of parasites include:
Biopsy is normally done on snips of gill, skin scrapings, or small pieces of fin. These can be done on live fish as we did in the lab. In the lab, we also did samples on freshly sacrificed fish, looking at liver, kidney, gills, and intestines. For those interested in biopsy and necropsy, which I think is necessary for proper diagnosis, I would suggest reading the text of Dr. Gratzek's book, "The Science of Fish Health Management", and then practicing on your own or with someone that has done it before. It was also noted in lecture, that many times bacterial infections occur secondary to parasitic infections, and for this reason when treating for parasites one must many times treat for bacterial infection as well.

The major external protozoan parasites that we see in our hobby are Ich, Chilodonella, Oodinium, Trichodina, Tetrahymena, and Epistylis.

Ich or Costia

is a round, ciliated organism which is covered by a cyst. It appears as white spots over the body of the fish, and it can destroy gills and cause respiratory distress. Medications can only kill the free-swimming forms, therefore, treatments have to be done every 5 days for 3 treatments. Ich treatment: 1. increase water temperature to 80 degrees 2. change water every day to dilute ich 3. use UV filtration 4. use Formaldehyde at 25ppm (100cc/1000gal) 5. use salt at a concentration of 0.3%

Chilodonella

is a quick killer of fish that appears as mucous over the eyes and skin, respiratory distress, and clamped fins. Diagnosis is by microscopic scrapings of gills and skin. Treatment is 0.3% salt (2.5lbs/100gal).

Oodinium

also called "velvet", appears as a fine dust on fish on the gills and skin. Diagnosis is done by microscopic scrapings. It is treated by formaldehyde at 25ppm or with acriflavine at 5 to 10 ppm, however acriflavine turns the pond water yellow.

Trichodina

attacks the gills and can affect pond fish. Diagnosis is done by microscope and treatment is the same as for Ich.

Tetrahymena

is sometimes found in pond fish. It causes necrosis and hemorrhage, eye bulge, and fin rot. There is no treatment and it is fatal to fish.

Epistylis

appears as white tufts on the ends of fins and occurs in ponds with high organic content. Diagnosis is by microscope, and treatment includes swabbing the area with iodine and using formaldehyde at 25 ppm.
As one can see, most of these parasites are treated with salt at 0.3% and formaldehyde as 25 ppm. For the hobbyist, there would be no reason to differentiate the parasites. More on parasites will appear in my next article.

Fish Health Management
(Part 5)

by Dr. Arthur Lembke

The lectures on Fish Health Management presented by Dr. Gratzek continued to discuss other pond parasites.

Monogenetic Trematodes

or flukes are very common in the koi hobby. The two types are Dactylogyridae (gill flukes) and Gyrodactylidae (skin flukes). Gill flukes appear with rapid respiratory movements, clamped fins, flashing, lethargy, and death. They can cause hyperplasia, destruction of gills, and asphyxiation. Gill flukes are easily diagnosed on mucous scrapings under a microscope. Gill flukes are egg_layers and to get rid of the disease three treatments must be given 5 to 7 days apart.
Skin flukes can appear as hemorrhage, excessive mucous, ulcerations, and tail rot. Many times they lead to secondary bacterial infections. Skin flukes are live_bearers and only require one treatment.
Treatment for both gill and skin flukes includes:

Leeches

are small worms of about 0.2 to 0.4 inches. They frequently are introduced by plants and snails and can carry mycobacteria infection. Plants should be treated with alum (1tbsp/gal of water) before being placed in the pond. Trichlorofon or formaldehyde can be used in the pond once infected.

Crustaceans

that affect our koi are anchor worm and fish lice. Anchor worms are seen as wormlike organisms sticking out of a hole in the fish where the female burrows its head. They can cause hemorrhage and secondary bacterial infections. Fish lice are disc shaped, transparent, and move freely around the fish. Secondary bacterial and fungal infections many times follow infestations.
Anchor worm and fish lice are both killed by Dimilin at 2ppm in one treatment. Trichlorofon at .25ppm can be used for 3 treatments 5 days apart. Fish lice will fall off in salt dip or potassium permanganate dip (50_70ppm) for 15 seconds.

Sporozoans

are another type of parasite. The two seen most often in our hobby are Coccidia and Mitraspora. They both affect goldfish and can form nodules on the fish. Coccidia is observed in goldfish in cold water. It can cause lethargy and emaciation as it attacks the intestines. Diagnosis is done through intestinal scrapings. Mitraspora causes bloating of the fish due to kidney damage. It mostly appears in September and October. The disease is transmitted in the spring through the urine.
There is no treatment for these sporozoan infections. One can only control the spread of the disease by removal of dying fish, avoiding feeding of live foods, and disinfecting ponds by liming and drying.

Internal worms

Digenetic trematodes appear in the intestines of the fish. They have a complex cycle involving birds and swine, and are rarely found in retail fish, however fish out of mud ponds can be infected. Once fish are infected they can not be treated. Tapeworm is found attached to the intestinal walls. It is treated by using prazinquantel at 2ppm. Roundworms can be found in the intestine and also can be seen in necropsy as cysts in the muscles. Initially, it can be seen protruding from the anus of the fish. Roundworms are treated by using Panacur at .25% of food. Roundworms have an intermediate host of daphnia or tubifex. Therefore, to stop the spread of the disease, avoid feeding live food.

Bacterial infections will be the subject of my next article.

Fish Health Management
(Part 6)

by Dr. Arthur Lembke

In this article I will review the information on bacterial disease given at the Fish Health Management course by Dr. Gratzek. First, it is important to know that not all bacteria cause disease. In the lab at the course, we grew many bacteria out of the water of healthy aquariums. Among these were benign bacteria that never cause disease (i.e. nitrifying bacteria), opportunistic bacteria that only cause disease under the right conditions (i.e. stress), and primary pathogens that always cause disease. Bacterial infections can be external or internal. Fish can become lethargic, lose spatial orientation, hemorrhage, develop ulcers, have frayed fins, become discolored, develop stomach distention or popeye.
Factors that predispose fish to bacterial infection:


One can avoid bacterial infections by reducing stress on the fish. This is done by better nutrition, improved water quality, stabilizing water temperature in pond, and quarantine of new fish. Diagnosis of bacterial infections is done in diagnostic laboratories. Fish must still be alive when they arrive at the lab. Samples of internal organs can be taken shortly after killing the fish. Samples can be taken of lesions if the external part of the lesion is sterilized and a sample is taken from just under the surface of the lesion.

Mycobacterium

is a chronic progressive disease. It is seen as emaciation, popeye, frayed fins, chronic ulcers, and decreased appetite. It generally affects older fish. It is controlled by maintaining water quality and removing sick fish from the pond. Most antibiotic treatments are ineffective. Hobbyists should be aware that this bacteria can be transferred to humans. Therefore, persons with cuts on their hands should wear gloves when cleaning around ponds. Aeromonas is the most common bacteria seen in lesions of koi.

Aeromonas

is always found in the pond and infections normally follow stress due to recent shipment, handling, parasites, and viruses. When external signs are present, they may include hemorrhage in and around the gills and anal area. Ulcers can occur any place on the fish. When systemic infection occurs, you will normally see abdominal distention and popeye. Aeromonas can be isolated from kidneys of infected fish. Treatment includes changing water, cleaning wounds, 0.3% salt in pond water to ease osmoregulation, and injecting fish with antibiotics. Dr. Gratzek's favorite is Chloramphenicol at 0.5ml to 1.0ml intraperitoneally every other day for 3 days. Baytril can also be used for injection. Dr. Gratzek preferred intraperitoneal injections to intramuscular injections.

Pseudomonas

appears as fin and body ulcers, many times accompanied by Aeromonas infection. Therefore, treatment remains the same as for Aeromonas, and there is no need to differentiate between the two bacteria.

Yersinia

can attack carp, although it is mostly seen at the wholesale level. It appears as hemorrhage of the mouth and throat. hemorrhage at the base of the fins, lethargy, popeye, and darkening of the skin. Antibiotics in the food will generally control the infection. If hemorrhage appears, injection is a better treatment.

Columnaris flexibacter

also occurs in koi. It appears in warm water and can be seen as fin and body rot, saddleback lesion, mouth fungus, cloudy eye, gill disease, or even death with no lesions. Antibiotics used to treat this infection include sulfa drugs, tetracycline, and nitrofurans. However, since Aeromonas often is seen in conjunction with this infection, antibiotic injection may still be the best treatment.
As a personal note, I would add that most bacterial infections appear as ulcers, and once ulcers appear injection of fish should be considered. If you are not comfortable with giving injections, then antibiotics can be added to food and water. If too many antibiotics are used for too short a time or at too low a dose, bacteria can become resistant to the antibiotics. This must be avoided as there are a limited number of antibiotics available to the hobbyist for treating bacterial infections.

Organics in the pond water can alter the amount of antibiotic available for the fish to absorb. Therefore, Dr. Gratzek recommends doing a water change before adding antibiotics to the water and a major water change 4 hours later to avoid exposing the fish to low doses of antibiotic over long periods of time. Water hardness may also affect the dosing level of antibiotics. Antibiotics can be added to food, and Dr. Gratzek suggests mixing it in cod liver oil to make it stick to the food. His instructions for mixing food include using 100 to 250mg of antibiotic mixed with a shot glass of cod liver oil added to 1 and 1/2 cups of food. Then lay out the food to dry and blot. For bacteria in general, Dr. Gratzek suggests using formaldehyde first and then antibiotics. Guidelines include using correct dose, minimal time, ending treatment by water change after 4 hours, aeration, and stop filter. Experiments were done and the results suggest that of all the medications and antibiotics we use in our ponds, the only one that seems to harm the filter is methylene blue. Fungus and viruses will be the topic of the next article.

Fish Health Management
(Part 7)

by Dr. Arthur Lembke

This article will focus on the discussion of fungus and viruses as presented by Dr. Gratzek at the course on Fish Health Management.

Saprolegnia

is the most common fungus found in koi. It shows as a white, fuzzy mass on the fish. Lesions often occur just forward of the dorsal fin and can be associated with a preexisting wound. Predisposing factors include presence of another disease, stress, and temperature changes. Lower water temperatures favor the growth of the fungus. Malachite green is the primary mode of treatment. It can be painted on the lesion, used as a bath of 2ppm for 30 minutes, or used at 0.1ppm for long term. Stop filtration and do water changes every 2_3 days.

Viruses

can infect koi as well. Viruses are the least studied of all the diseases because of cost restraints. They can only be cultured on living cells and can only be seen on electronic microscopes. They can be tested for by using a PLR Test or fluorescent microscopy. A viral disease is suspected after all other possible causes have been eliminated. There are no antiviral drugs available for fish. To stop spread of the disease, one should quarantine fish for at least 21 days.

Lymphocytosis

can affect goldfish and koi, resulting in an increase in the size of cells up to 50,000 times their normal volume. Cells can enlarge on the fins, eyes, and mouth. It can spread from fish to fish by contact of the virus with openings in the skin due to handling, sores, or parasites. Masses can be surgically removed and then cauterized.

Goldfish Iridovirus

can affect fish and attach to the swimbladder.

Spring viremia of carp

can cause hemorrhages and dropsy during the spring months.

In all the previous articles on fish health management, I have reported the facts as presented at the course and have not made any of my own suggestions. At the risk of over simplifying the diagnosis and treatment process, I would like to summarize and give my own diagnostic process for koi.
If a fish flashes in the pond, first check ammonia, nitrite, and pH of the pond. If these are not in the safe range, then correct them. If these are corrected or they were normal, then do a mucous scraping and check for parasites or protozoa. If anchor worms or fish lice are present, treat with Dimilin if you have it, or use Trichlorofon for 3 times. If flukes or protozoans are present, treat with formaldehyde 3 times. As with any disease, always add salt to the water at 0.3% concentration.
If white, fuzzy patches appear, consider fungus as the problem and use 0.3% salt and malachite green.
If hemorrhage, ulcers, or fin or tail rot are noted, then always consider bacterial infections as the problem. First choice here is injection of Chloramphenicol, Baytril, or Azactam. I prefer intramuscular injection, although Dr. Gratzek preferred intraperitoneal injection. Second choice would be antibiotic food, and last choice would be antibiotics added to the water. When treating for bacteria, always start with formaldehyde in the pond because many infections follow parasite infestations.

Art's Medicine Chest

I hope these articles have helped give information that is useful to you. If you have the chance, I would highly recommend that you take the Fish Health Management course offered at the University of Georgia
Yours in koi,
Dr. Arthur Lembke