Aquatic Disease

A Veterinary Medical Primer

Updated: Wednesday, November 18, 1998

Index:

Part I: Introduction

Symptoms

1. Who is affected?
2. What is affected?

Differential Diagnoses

Diagnosis and Pathogenesis

1. Stress
2. Trauma
3. Genetic Disorders
4. Tumors and other forms of cancer
5. Poisoning
6. Pathogens

Treatment

1. Prophylaxis
2. Symptomatic, supportive, and/or palliative treatment
3. Cure
4. Euthanasia

Sources

Author's Note:

Due to the complexity this article is beginning to have, and due to a change in my work schedule, the updates will unfortunately come at a slower pace than has been the case in the past. I am still diligently working on this project and am trying to make this one of the most complete projects on the "Net"... Please have patience with me and look in often. More updates are on the way!

Wednesday, February 11, 1998:

• Completely changed the format of the article.
• Removed the "Antibiotics Section" as a separate article.

How does the disease manifest itself? -- Symptoms

What diseases fit this picture? -- Differential Diagnoses

What are the contributing and causative factors in the disease? -- Diagnosis and Pathogenesis

What is my course of action? -- Treatment

Index:

Part I: Introduction

Symptoms

1. Who is affected?
2. What is affected?

Differential Diagnoses

Diagnosis and Pathogenesis

1. Stress
2. Trauma
3. Genetic Disorders
4. Tumors and other forms of cancer
5. Poisoning
6. Pathogens

Treatment

1. Prophylaxis
2. Symptomatic, supportive, and/or palliative treatment
3. Cure
4. Euthanasia

Sources

• How does the disease manifest itself ?
• When assessing the big picture it is important to know what the norm is.
• Spend time observing the tank when no disease is apparent.
• Study, read about, and observe the individual animals before purchasing them.
• Know what the normal behavior is for the animal.
• Only when the norm is known can an accurate assessment of the symptoms be made.
• Furthermore, by knowing what the norm is, disease can often be caught far earlier, in the beginning stages, and be treated with more success.

• Of one species.
• Of several species.

• Of one species.
• Of several species.

Locomotor dysfunction:

• Swim with head down.
• Swim upside down.
• Swim rotated to one side.
• Whirling, wobbling
• Staggering
• Rocking
• Cannot swim
• Lies flat on the bottom.
• Jerky fins
• Cannot remain motionless in the water.

• Rapid
• Slow
• Labored

• Fish is lethargic.
• Fish "hangs" under the surface.
• Flee reflex is absent -- does not dodge fish net or other fish.

• Fish jumps or darts around.
• Fish hits the side of the tank.
• Fish scrapes itself on objects in the tank.

• One or more fish separate themselves from the others.

• Darker
• Lighter
• More intense
• Faded

• Weight loss
• Skinnier
• Swollen body

• Curved spine
• Lumps
• Tumors

• Flat
• Translucent, white
• Round, red, inflamed
• Irregular, red
• Raised
• Round, white
  • Sand or grit-like
  • Isolated
• Round, dirty white to yellow
• Red

• Bloody patches
• Red-bordered lesions

• White, thready, cotton-like
• "Lumps" under the skin or in the muscle.

• Fluid filled
• Air filled

• Outlined in white.
• Raised

• Frayed
• Split
• Cloudy
• White edged and growing continuosly shorter
• Missing
• Nodules between rays
• White dots
• Velvety coating

• Protuding ("Pop-Eye")
• Sunken in, hollow
• Empty looking and highly reflective
• Cloudy
• Visible spots
• Visible crustations, worms, or other animals

• Filaments lose color and become lighter.
• Filaments are a very pale pink.
• Filaments become cloudy to white.
• Filaments are swollen.
• Filaments are slimey and stick together.
• Filaments are necrotic (dead tissue).
• Filaments fall out.
• Small white dots appear on the filaments.
  • 0.5 to 1 mm in freshwater fish.
  • 2 mm in saltwater fish.
  • Stuck tight and resemble crustations.
  • Cannot be removed.
• Gills become flecked.
• Cotton-like thready growths on the operculum (gill cover) or filaments.

• A knowledge of fish anatomy.
• A knowledge of basic dissection techniques.

• Slimey
• White
• Yellow
• Hangs on fish like a thread
• Contains eggs of parasites

• Cloudy
• White

Differential Diagnoses

Index:

Part I: Introduction

Symptoms

1. Who is affected?
2. What is affected?

Differential Diagnoses

Diagnosis and Pathogenesis

1. Stress
2. Trauma
3. Genetic Disorders
4. Tumors and other forms of cancer
5. Poisoning
6. Pathogens

Treatment

1. Prophylaxis
2. Symptomatic, supportive, and/or palliative treatment
3. Cure
4. Euthanasia

Sources

• Once all of the symptoms have been noted comes the difficult part.
• What diseases fit this picture?
• It is important not to hasten through this step and start shooting in the dark.
• Only after all the facts have been carefully weighed and a firm diagnosis has been made can treatment actually begin.
• This is the step where lab work and pathology come in.
  • Microbiology
  • Skin scrapings
  • Biopsies and samples
• In severe cases supportive, symptomatic treatment can be started as a temporary palliative measure.

Index:

Part I: Introduction

Symptoms

1. Who is affected?
2. What is affected?

Differential Diagnoses

Diagnosis and Pathogenesis

1. Stress
2. Trauma
3. Genetic Disorders
4. Tumors and other forms of cancer
5. Poisoning
6. Pathogens

Treatment

1. Prophylaxis
2. Symptomatic, supportive, and/or palliative treatment
3. Cure
4. Euthanasia

Sources

• What are the contributing factors and causes of the disease?
  • Life cycles of parasites.
  • Incubation periods.
  • "Normal" length and course of disease.
  • Possible secondary infections.
• After a firm diagnosis has been made one must look closely at the cause of the disease.
• With this information at hand one can choose the best course of treatment.

• Stress is one of the major factors contributing to disease.
• Stress is also one of the easiest factors to control.
• Proper setup, good husbandry, and maintenance are the key factors to controlling stress.
• Stress cannot be totally eliminated.
• Some stress ("good stress" or "eustress") is necessary.
• "Bad stress" or "distress" should be avoided.
  • Water quality
  • Lighting
  • Temperature
  • Population density
  • Nutrition
  • Parasites
• I will deal with stress in more detail in an upcoming seperate article.

• Water quality is of the utmost importance in preventing disease.
• Accumulation of fecal materials, organic wastes, and other polutants is extremely stressful for the tank inhabitants.
• Good filtration and regular water changes are beneficial to the water quality:
  • Skimmers
  • Mangroves or other plant-based filters.
  • Chemical filtration - where applicable.
  • Ozone, UV sterilizers, and wet-dry filters have fallen somewhat from grace in the hobby.
  • Plenum systems are still being vigorously debated.

• "A little is good -- a lot is better" is not true.
• Frozen foods contain large amounts of phosphates if not rinsed before adding to the tank.
• Liquid foods can contain phosphates.
• Flake foods should be used sparingly.
• It will not harm the fish to not feed them one or two days a week.

• Dead animals (fish or invertebrates)
• Dead microbes and/or parasites resulting from treatment.

• Released from microbes.
• Released from decorations and rock.
• Broken heaters, light bulbs, and other equipment.

• Fat soluble vitamins (A, D, E, and K) can be overdosed and toxic.
• Water soluble vitamins (B vitamins and ascorbic acid) are difficult to overdose.

• Fat Soluble

• Fat Soluble

• Fat Soluble

• Fat Soluble

• Water soluble

• Water soluble

• Necessary for some types of invertebrates.
• Wrasses and other types of fishes sleep buried in the sand.

• Sharp edges
• Large, loose rocks (danger of falling!)

Heavy metals

Be careful when adding decorations.

• Cups, plates, and some types of rock can be sources of heavy metal contamination.
• Be safe and use only "aquarium certified" decorations.

Mercury thermometers and fluorescant light bulbs:

• Can be extremely hazardous when broken, both to tank inhabitants and to human beings.

• Cyanide is used by some unscrupulous people to catch fish in the wild.
• Acute and chronic cyanide poisonings are difficult if not impossible to treat.
• If at all possible purchase only tank raised fish or fish that have not been caught with cyanide.
• Not only is there a better chance of the fish surviving, but a stop will be put to this outrageous practice.

• During the process of breaking down the dead tissues (decay), substances are produced that are in themselves toxic.
• Nitrites, nitrates, and phosphates are also released -- either as byproducts or as stored substances.

1. Exotoxins:
   • Some microbial pathogens relase toxins into their surroundings.
   • These toxins are what cause the illness.

1. Endotoxins:
   • Some microbial pathogens produce toxins as a part of their metabolic process.
   • These are released when the organism dies off.
   • This must be taken into account when treating systems.
   • If a large amount of these pathogens are present when treated then large amounts of toxins will be released into the system.
   • Extra filtration is needed to compensate for the extra load of toxins.
2. "Break-down" products of the dead organisms:
   • Metabolites in the normal break-down process of the dead organism can be toxins in themselves.

• Safe for most fish.
• Highly toxic for invertebrates.

• A fat soluble vitamin.

• A fat soluble vitamin.

• A fat soluble vitamin.

• A fat soluble vitamin.

• A water soluble "vitamin."
• Ascorbic acid is not a vitamin in animals (except guinea pigs).
• When metabalized, ascorbic acid is broken down into several componants.
• One of these componants is oxalic acid.
• Oxalic acid forms calcium oxalate in the presence of calcium ions.
• Oxalates are practically insoluble and collect in the tubules in the kidneys.
• This in turn clogs the tubules and effectively shuts down the kidneys.
• This can lead to death in severe cases.
• A complete shutdown due to oxalates is practically intreatable in fish. The only effective means of treatment is surgery.
• Animals can be acclimated to higher doses of oxalates if done slowly.
• Ascorbic acid is an important means of treatment in many cases as demonstrated by Albert Thiel.
• It is important to follow the regimen described in the article ( Web Site and on the NetClub).
• Add tablets to sump or pre-dissolve powder in cold water before adding to tank. This is to prevent the fish from actually eating the pure substance and possibly overdosing on it.

• There are too many species of parasites to mention them all.
• It is generally not as important to know the exact species of parasite.
• It is more important to know what family of parasite (e.g. tapeworm, roundworm, skin flagellate, etc.) is present.
• Treatment can usually be done by family.
• The following list shows a small portion of the parasites that must be dealt with!
• The life cycle of the parasite is of utmost importance.
• By knowing the life cycle one can determin the correct treatment regimen.
• Without knowledge of the life cycle treatment could be cut short as the larval forms of the parasite are not taken into account.

Skin parasites

Protozoa (one-celled organisms)

• Costia necatrix (formerly Ichthiobodo)
• Oodinium spp. (Dinoflagellates)
• Amyloodinium spp. (Dinoflagellates)
  • Amyloodinium ocellatum

• Ichthyophthirius multifiliis ("Ich")
• Brooklynella hostilis
• Tetrahymena pyriformis
• Vorticella spp.
• Trichodina spp.
• Chilodonella spp.
• Glossatella spp.
• Carchesium spp.
• Epistylis spp.

Metazoa (multi-celled organisms)

• Monogenetic, adult
  • Gyrodactylidea
• Larval stages (metacercaria) of various species

• Copepods
  • Ergasilidae
  • Lernaeidae
• Argulidae (lice)

Gill parasites

Protozoa (one-celled organisms)

• Costia necatrix
• Cryptobia spp.
  • Cryptobia branchialis
• Oodinium spp.
  • Oodinium pillularis
  • Oodinium limneticum
  • Oodinium ocelatum
  • Oodinium vastator
• Amyloodinium spp.
  • Amyloodinium ocellatum

• Myxobolus
• Myxidium
• Myxosoma

• Nosema spp.

• Ichthyophthirius multifiliis ("Ich")
• Chilodonella cyprini
• Brooklynella hostilis
• Tetrahymena pyriformis
• Vorticella spp.
• Trichodina spp.
• Trichodinella spp.
• Tripartiella spp.
• Dipartiella spp.

Metazoa (multi-celled organisms)

• Monogenetic, adult
  • Dactylogyridea
• Digenetic, adult
  • Azygia lucii

• Philometra, adult

• Copepods
  • Ergasilidae
  • Lernaeidae

Eye parasites

Protozoa (one-celled organisms)

• Myxobolus spp.

Metazoa (multi-celled organisms)

• Diplostoma spp., larva (metacercaria)

Endoparasites

Intestinal Parasites

Protozoa (one-celled organisms)

• Hexamita spp.
• Spironucleus spp.
• Trichomanas spp.
• Bodomonas spp.
• Opalinidae
  • Protoopalina symphysodonis

• Entamoeba spp.

• Eimeria spp.
• Calyptospora spp.

• Glugea spp.

Metazoa (multi-celled organisms)

• Crepidostomum farionis
• Azygia lucii
• Sphaerostoma spp.
• Bunodera spp.

• Caryophyllidea
  • Caryophyllaeus laticeps
• Pseudophyllidea
  • Triaenophorus spp.
  • Eubothrium spp.
  • Cyathocephalus spp.
  • Bothriocphalus spp.
• Tetraphyllidia
  • Rhinobothrium corymbum
  • Echeneibothrium dubium
  • Phyllobothrium spp.
• Proteocephalida
  • Proteocephalus spp.

• Ascaroidea (roundworms)
  • Contracaecum spp.
• Trichuroidea
  • Capillaria spp. (hairworms / filarial worms)
• Camallanoidea
  • Camallanus cotti
  • Camallanus lacustrus
• Spiruroidea
  • Rhabdochona denudata
• Oxyuroidea (pinworms)

• Acanthacephalus spp.
• Echinorhynchus spp.

Blood parasites

Protozoa (one-celled organisms)

• Trypanoplasma borelli
• Trypanoplasma cyprini

• Cryptobia spp.

• Trypanosoma spp.

• Haemogregarina spp.

• Leucocytozoon spp.

Metazoa (multi-celled organisms)

• Digenetic
  • Sanguinicola spp.
  • Aporocytele spp.
• Dracunculoidea
  • Philometra sanguinea

Parasites of the body cavity

Cystic

• Cotylurus spp.

• Contracaecum spp.
• Anasakis spp.

Free in the body cavity

• Amphilina foliacea

• Schistocephalus solidus
• Ligula intestinalis
• Diphyllobothrium spp.
• Tetraphyllidea, plerocercoids
• Trypanorhynchidea, plerocercoids

• Philometra spp.

Parasites of the kidneys

Protozoa (one-celled organisms)

• Eimeria scardinii
• Eimeria leucisci

• Hoferellus cyprini
• Sphaerospora spp.
• Leptotheca spp.
• Myxoproteus spp.

Metazoa (multi-celled organisms)

• Posthodiplostomum spp.

Parasites of the liver and spleen

Protozoa (one-celled organisms)

• Eimeria metchnikovi
• Eimeria cruciata

• Coccamyxa spp.
• Alatosporum spp.
• Leptotheca spp.
• Ceratomyxa shasta

Metazoa (multi-celled organisms)

• Posthodiplostomum spp.

• Triaenophorus spp.
• Diphyllobothrium latum

• Capillaria petruschewski

Parasites of the air bladder

Protozoa (one-celled organisms)

• Eimeria gadi

• Glugea spp.

Parasites of the muscles

Protozoa (one-celled organisms)

• Nosema spp.
• Glugea spp.
• Thelohania spp.
• Pleistophora spp.
  • Pleistophora hyphessobryconis

• Myxidium spp.
• Myxosoma spp.
• Myxobolus spp.
• Sphaerospora spp.
• Ceratomyxa spp.
• Hennguya spp.
• Hoferellus spp.

Metazoa (multi-celled organisms)

• Posthodiplostomum cuticola
• Opistorchis spp.

• Pseudophyllidea spp.

• Sphyrion spp.
• Sarcotaces spp.

Parasites of the nervous system and/or bones

Protozoa (one-celled organisms)

• Myxosoma cerebralis

• Cryptobia spp.

Metazoa (multi-celled organisms)

• Diplostomum spp.

Index:

Part I: Introduction

Symptoms

1. Who is affected?
2. What is affected?

Differential Diagnoses

Diagnosis and Pathogenesis

1. Stress
2. Trauma
3. Genetic Disorders
4. Tumors and other forms of cancer
5. Poisoning
6. Pathogens

Treatment

1. Prophylaxis
2. Symptomatic, supportive, and/or palliative treatment
3. Cure
4. Euthanasia

Sources

How toxic / lethal is the treatment?

• The greater the difference is between the toxicity to the pathogen and the toxicity to fish, the safer the substance.
• If the substance is both highly toxic to the pathogen and to the fish then there is less tolerance in making mistakes in the dosage!

What is the concentration of the agent going to be at the affected site?

• This depends on several things:
• How the substance is administered:
  • Per os (by mouth)
  • Subcutaneously
  • Intramuscularly
  • Intravenously
  • Transcutaneously
• How well the substance is absorbed into the body.
• How well the substance is transported to the affected site.

• Preventing disease in the first place is always better than treating it after the fact.
• Too late after symptoms are apparent.

• B-Vitamin complex
• Vitamin C (see comments under " Poisoning")

• Vitamin A
• Vitamin D
• Vitamin E
• Vitamin K

• No sharp objects.
• Make sure all rock and decorations are firmly placed and cannot topple over onto unsuspecting fish or invertebrates.

• If using high-tech equipment make sure it is set up properly and calibrated often.
• Do not over- or underskim.

• See comments under " Poisoning."
• See Albert Thiel's articles on his Web Site and on the NetClub.

• Only a temporary solution.
• Good while assessing the situation and firming up a definite diagnosis.
• Usually only necessary when the disease has progressed into the more severe stages and until a definitive course of treatment can be decided on.
• Often critical in the management of infectious diseases.

• Caution!
• Some fish and invertebrates do not tolerate large temperature increases well.
• Only of limited value.

• Caution!
• Lowering the SG to 1.018 to 1.020 can result in alleviation of some parasitic symptoms.
• It is not tolerated well by some types of fish and corals.
• Only of limited value.

• Generally better tolerated than lowering the SG in marine tanks.
• Can be beneficial as a suplimental treatment.
• This is not a cure.
• Higher dosages can be detrimental to plants.
• Approximately 1 g per 12.5 liters of water for soft water fish.
• Approximately 3 g per 10 liters for hard water fish.

• Baths and dips are good to remove external parasites, treat some internal infections, and are good for external wounds.
• They are not however, good for use as a "cure."
• If the underlying cause is not removed (e.g. parasitic life- cycle broken) the problem will only reoccur.
• Since baths and dips rely on their extreme toxicity to the pathogen, they generally put the animal being treated under a lot of stress.
• The larger the difference between the toxicity to the pathogen and the toxicity to the animal being treated, the safer the treatment.
  • E.g. copper is fairly safe to vertebrates and fairly to extremely toxic to invertebrates. It is thus safe as treatment for invertebrate infestation of fish (parasites).
  • It cannot be used in systems with desirable invertebrates though.
• One should only submit the animals to as many baths or dips as absolutely necessary to solve the problem, and only in conjunction with other forms of treatment remedying the underlying cause.
• Never rely solely on baths or dips as a cure!

• See comments under " Poisoning."
• See Albert Thiel's articles on his Web Site and on the NetClub.

• VERY important in fostering a healthy immune system.

• Protein content.
• Fat content.
• Carbohydrates.

• B-vitamins to stimulate the appetite.
• Ascorbic acid for the immune system.

• The treatment of choice.
• Only possible if an exact diagnosis has been made.
• If possible obtain a sensitivity test on any pathogens (your veterinarian should be able to help).
• Choose a treatment that is aimed at the specific pathogen if possible.
• Pay strict attention to dosages -- too much can be toxic; too little can foster microbial resistance.
• Drug interactions must be considered -- DO NOT mix drugs indiscriminately!

• See separate article on this site.

• There a few available anti-viral drugs.
• They are very expensive.
• Their value is debatable.

• See comments under " Poisoning."
• See Albert Thiel's articles on his Web Site and on the NetClub.

• Only to be considered as a treatment in the widest sense.
• Sometimes humane killing of the animal is the best course of action.

Index:

Part I: Introduction

Symptoms

1. Who is affected?
2. What is affected?

Differential Diagnoses

Diagnosis and Pathogenesis

1. Stress
2. Trauma
3. Genetic Disorders
4. Tumors and other forms of cancer
5. Poisoning
6. Pathogens

Treatment

1. Prophylaxis
2. Symptomatic, supportive, and/or palliative treatment
3. Cure
4. Euthanasia

Sources

• There are many good reference books to be purchased.
• Make use of any and all resources possible.
• I have compiled information from the sources below and added my own knowledge to it -- but the more you read up on the subject -- the better off you are!

1. The Freshwater Library
2. The Saltwater Library

Please return to this article. It is far from finished and will be updated in the near future!