Anatomy of a Fish

anatomy of a ﬁ sh

Internal Anatomy of a Fish

Gill Filaments Anterior + Gill Arch Posterior Kidney

Brain

Swim Bladder Heart Gonad Liver Stomach Gall Intestine Spleen Bladder Cloaca

External Anatomy of a Fish

Dorsal Fin Operculum Adipose Fin Caudal Nostril Fin

Lateral Line

Barbel

Sensory Slime Pits +Skin Anal Fin Pectoral Pelvic Fins Fins Cloaca

TECHNICAL NOTES ANATOMY OF A FISH 31 stress and the immune system

The Commercial Handling of Fish Generally speaking, aquarium ﬁ sh are remarkably hardy creatures, and providing that we not only keep them in an environment that suits them, but also that we feed them properly, they are likely to remain healthy. Conversely, if we stress them sufﬁ ciently they are likely to become sick.

Diagrams Illustrating the Effects of Environment on Fish Health

LATENT INFECTION

DECLINING ENVIRONMENT IMPROVING FISH HEALTH

DECLINING FISH HEALTH RECOVERING ENVIRONMENT

DISEASE

DEATH

At times we inadvertently subject ﬁ sh to stressful conditions. Our aim must be to minimise the degree, the duration and the frequency of stress.

The following list contains a few examples of what aquarium ﬁ sh may be subjected to before or after they reach the home aquarium.

• The shipping process/transport stress • Pollution • Crowding • Pathogens • Lowered oxygen levels • Electrical changes • High carbon dioxide levels • Aggression by other ﬁ sh • Abrupt changes in temperature, hardness, • Excessive water velocity and conductivity • Photostress • Exposure to ammonia, nitrite and other toxins • Noise or vibration • Psychological strain • Nutritional problems • Low or High pH • Injury

Relationship Of Stress To Disease Most aquarists would have had the experience of severe stress on fi sh, which has lead to almost immediate death. Recent studies have shown that an accumulation of a series of less severe stresses can cause delayed fi sh deaths, which may occur days after a non-lethal stress. A single stress changes the fi sh’s body functions, which enable it to adapt to the stress. If the stress continues, the normal disease fi ghting function of the fi sh’s body is exhausted, resulting in disease organism invasion.

HOST PATHOGEN

DISEASE

ENVIRONMENT

TECHNICAL NOTES 32 STRESS AND THE IMMUNE SYSTEM stress and the immune system

Host + Pathogen + Unsuitable Environment = Disease It therefore follows, that a situation free of any one of the above mentioned three components, will reduce or remove the possibility of disease.

The Immune System Fish live in an environment containing many bacterial, fungal, viral and other pathogenic agents. If they did not have a good defence system, they would be swamped and consumed. We now know that ﬁ sh have a well-developed immune system, made up of an intricate network of chemical protectors and microbiological killers.

The immune system of ﬁ sh is able to cope with many bacteria, which are found on the surface and within the ﬁ sh. Stress upsets this balance in favour of the harmful bacteria Stress Scale

PATHOGEN IMMUNE (50%) SYSTEM (50%)

Skin and Mucous Coating The body slime and skin is the primary defence barrier. The mucus prevents invasion by continuous loss and replacement. The skin is equipped with enzymes, antibodies and defence cells known as macrophages, which digest and destroy bacteria. Hence the importance of ensuring the skin is not damaged physically, chemically, or by parasites.

Macrophages are cells found throughout the body, which are capable of destroying bacteria by a process involving engulfment and enzymatic digestion. These cells, which are microscopic are very important in protecting the ﬁ sh from bacterial infection. Their efﬁ ciency is reduced by hormonal changes resulting from stress.

Speciﬁ c Defence Mechanisms Fish, like humans, can be immunised against bacteria and at least one protozoan (white spot disease). This can happen by natural exposure, or by vaccination. However, at this time, there are no vaccines commercially available to the aquarium trade in Australia. a) Tests have shown that acquired speciﬁ c immunity is not passed on to the offspring. b) Fishes’ immunity seems to lessen at lower temperatures.

This may explain why problems (e.g. goldfi sh ulcer disease) often develop with pond fi sh, in changing seasons, with rising temperatures. Increasing water temperatures probably increases the rate of replication of bacteria, which is not matched by the fi shes’ immune (defence) system.

Summary Our role is to eliminate as much stress as possible from our fi sh, thus minimising the likelihood of disease. We are fortunate that aquarium fi sh have an effective immune system, which is working for their well being, and indirectly, for our good at the same time. When we use medication on our fi sh, all we are doing is tipping the balance in favour of the fi sh, by hindering the disease organism.

TECHNICAL NOTES STRESS AND THE IMMUNE SYSTEM 33 disease symptoms and treatments

Illness Identiﬁ cation The ﬁ rst step to determining a treatment regime is to ascertain the cause of the problem.

Is it Environmental or Pathogenic Disease?

If it is pathogenic disease is it Parasitic or Bacterial?

These ﬁ rst important steps require a thorough knowledge of acceptable parameters for water quality, and the ability to diagnose diseases, based on changes in behaviour, and external symptoms. Use of a microscope, for examining skin scrapings, and gill biopsies is strongly recommended.

External Signs 1. Fish behaving abnormally; keeping to the top or bottom of an aquarium; erratic swimming; shimmying; poor equilibrium; scratching or scraping on objects. 2. Clamped ﬁ ns. 3. Rapid respiration. 4. Abnormal colour, cloudy eyes, darkening, loss of colour. 5. Loss of appetite. 6. Skin abnormalities, cotton-like tufts, lesions, white spots, excessive mucus, greyish patches, haemorrhages. 7. Swelling or bloating. 8. Emaciation

Poor water quality can induce the same symptoms as those caused by pathogenic disease. Before applying treatments check the following: 1. Is pH of water correct for the species? Is the water too acid or too alkaline? 2. Is water hardness and salinity correct for the species? Is water too hard or too soft? - Should water conditioner or extra salt be added? 3. Are their own waste products, ammonia, nitrites, nitrates etc poisoning the fi sh? 4. Is the tank water too old? Insuffi cient partial water changes? 5. Has water been contaminated by poisonous substances, such as fl y spray or pest strips, cigarette tobacco, metals or toxic chemicals, including possible overdose of medications? 6. Is the temperature correct? How long since you have checked your thermometer? 7. Are fi sh too crowded, or incompatible with each other? 8. Have fi sh been fed correctly - is the water polluted with uneaten particles, or are fi sh very thin and starving? 9. Is there suffi cient aeration and fi ltration to ensure adequate gas exchange? 10. Is there an anaerobic condition in the fi lter, producing toxic substances?

Water Quality Diseases Remember, many ﬁ sh die as a direct result of unsuitable water quality. Eg. Extremes in pH, ammonia toxicity etc. In less extreme cases, the stress of living in unsuitable water leads to the development of pathogenic disease.

TECHNICAL NOTES 34 DISEASE SYMPTOMS AND TREATMENTS disease symptoms and treatments

Treatment Rules 1. Do not medicate aquarium until after you have eliminated environmental factors as possible cause of symptoms. 2. Early action is an important factor in determining the success of treatment. Once a disease has been accurately diagnosed, do not waste time before treating. 3. Use effective medications. The wrong diagnosis may lead to improper selection of drugs, which could stress or kill fi sh. 4. If you are having problems with disease diagnosis, contact Aquarium Industries Vet Services for further advice. 5. Follow the manufacturer’s instructions carefully on all remedies. Many medications are highly toxic when overdosed. 6. By cleaning the fi lter and doing a partial water change of about 1/3 before treating, dilutes water-born pathogens, improves water quality, and usually makes the fi sh feel better. 7. REMOVE ACTIVATED CARBON BEFORE ADDING MEDICATION: Activated carbon removes medication quickly, rendering treatment ineffective.

Treating Disease The majority of pathogenic diseases encountered in an aquarium can be grouped into two broad categories:

PARASITIC, which can be seen either with the naked eye or with the aid of a microscope. BACTERIAL - If water quality is good, and parasites are not detected, then bacterial disease can be suspected.

Most medications used with aquarium ﬁ sh are administered via the aquarium water, as a long term, or permanent bath.

Recommended Reading The “T.F.H.” Handbook of Fish Diseases (TS 123) by Dieter Untergasser are highly recommended. These books should be in the library of every aquarium and pet shop.

The Disease and Symptom Treatment Chart (on the following pages) covers the more common aquarium ﬁ sh diseases.

If in doubt call:

*Excludes mobile phones

TECHNICAL NOTES DISEASE SYMPTOMS AND TREATMENTS 35 disease, symptoms and treatment chart sh for sh lter lter lter sh do not After 4 days change ½ the water, change After 4 days then repeat treatment if necessary treatment affect bio fi Vibravet cases Dose can be doubled for severe treatment affect bio fi Vibravet then ½ the water, change After 4 days repeat treatment if necessary treatment affect bio fi Vibravet approx 28°C Higher temperatures speeds up cure time instructions. manufacturer’s Follow worms anchor cold water In very dormant within goldfi stay may worms) months (see page on anchor Follow manufacturer’s instructions. manufacturer’s Follow Healthy and undamaged fi Healthy become infected with fungus sh lice Use Aquasonic Ichonex or spot white commercial any treatment Doxycycline (Vibravet) at (Vibravet) Doxycycline 5mg per litre (Vibravet) Doxycyline 250mg per 100 litres or any Use Para-gone worm anchor commercial treatment Use any tetracycline, tetracycline, Use any aquarium medication or (Doxycycline) Vibravet at 5mg / litre Use Para-gone or any or any Use Para-gone fi commercial treatment Any commercial fungus commercial Any cure, or use a cotton bud to paint affected area with Mercurochrome rst seen on sh at parasite, parasite, at sh sh sh ns and body rot. Primary ns and body sh scrape sh ns – fi Early stage hard to detect, few fi specks small white fi White mouldy patch on back or on back patch White mouldy If side, lesion deepens rapidly. losses occur untreated heavy lesions on the body Red ulcerative surface of goldfi 5 to 10mm Stiff rod-like parasites to fi long attached Mouth, fi line of infection is whitish/grey. Round to oval, fl Round to oval, approximate 10mm, transparent has 8 legs, grey/green colour, to fi attaches Tufts of fungus, resembling dirty Tufts on the grow cotton wool, white outside of the fi ed bacteria llis Aeromonas salmonicida nova var. Unidentifi Flexibacter columnaris & other bacteria & fungi Ichthyophthirius multifi Disease Name Disease Organism Symptoms Treatment Notes sh Ulcer Disease (GUD) Bacterial Neon Splitting Disease Splitting Disease) (False Goldfi Columnaris Disease External Parasites White Spot Anchor WormAnchor Lernaea Fish LiceFish Argulus Fungus Sarprolegnia Fungus Infections

TECHNICAL NOTES 36 DISEASE, SYMPTOMS AND TREATMENT CHART disease, symptoms and treatment chart sh have recovered carry out recovered sh have ukes are resistant to treatment Treatment should be repeated Treatment in 3-4 weeks instructions manufacturer’s Follow instructions. manufacturer’s Follow If fl use different product to treat. after 12 hours. Change 1/3 water can be toxic to Caution Formalin some species. After fi for 3 day every change 1/3 water to dilute medication to 4 days approx 28°C Higher temperatures speeds up cure time instructions manufacturer’s Follow uke cure sh food with cod avine Use Aquasonic Oodonex or commercial or any Vertonex spot treatment marine white Use any commercial Use any cure velvet or any Use Para-gone fl commercial Formalin Use a commercial green or & Malachite 30gm (6 teaspoons) sodium (salt) per 10 litres plus chloride treatment that contains any acrafl Use Aquasonic Ichonex or spot white commercial any treatment Crush 1 Drontal dog wormer Crush 1 Drontal dog wormer tablet for 10kg dog; mix into fi 100 grams for day every oil. Feed liver 7 days. sh rst seen on ns & scrape sh, reduced ns, reduced activity, ns, reduced activity, sh scrape sh ns, scraping, reduced activity, ns, scraping, ns – fi Pin head size white spots Pin head size white appear on fi and scraping activity Dusty gold appearance, fi Dusty gold appearance, listless, clamp fi clamped Dull appearance, fi increased breathing frequency skin, scraping, white Slimy clamped fi increased breathing frequency Early stage hard to detect, few fi specks small white fi Thin round, red worms Thin protruding slightly from the anus llis Dactylogyrus & Gyrodactylus Chilodenella, Costia Trichodina, Ichthyophthirius multifi Cammallanus spec. Disease Name Disease Organism Symptoms Treatment Notes Gill & Skin Flukes Skin DiseaseSlimy Fungus Infections White SpotMarine White Spot Cryptocaryon irrtans Camallanus (Toothbrush or Camallanus (Toothbrush worm) Paintbrush External Parasites Microscopic DiseaseVelvet Oodinium Worms

TECHNICAL NOTES DISEASE, SYMPTOMS AND TREATMENT CHART 37 white spot disease

The causative organism is Ichthyopthirius multiﬁ liis, a single celled protozoan, which grows to 1mm in diameter and can be seen with the naked eye.

Symptoms Infected fi sh twitch their fi ns and scrape or bounce off objects in the tank. Early in the infection, only a few spots can be seen, mainly on the fi ns. As the disease progresses the “spots” grow larger and more numerous. If left untreated the fi sh become covered in spots. Increased mucus production, as well as secondary bacterial and fungal infection, causes the fi sh to take on a slimy mouldy appearance, often with blood streaks showing on frayed fi ns. Listlessness, and hanging at the surface, are the usual fi nal symptoms before death. Small fi sh, such as neons, seldom show all these symptoms, as only a few parasites are needed to kill them. Under the microscope, the adult parasite can be seen to constantly rotate; is uniformly covered in cilia; and has a characteristic horseshoe shaped nucleus.

Life Cycle 1. Parasites invade the epidermis (skin) and grow within it. 2. Parasites digest ﬁ sh tissue (causing irritation) and eventually grow to adult size (approximately pin head). 3. Adult parasites leave ﬁ sh to reproduce at bottom of aquarium. 4. There they undergo a rapid division into numerous youngsters, up to 1000. 5. Young, free-swimming parasites (called tomites) burst from the cyst after 12 to 18 hours. This is the time most medications work best. 6. The complete cycle at tropical temperatures takes from 3 to 5 days, from 5 to 14 days at 15oC and even more than a month at temperatures below 10oC.

Control White spot is a common disease of tropical and goldﬁ sh, and can be found in aquariums, ponds, farmed and wild ﬁ sh. Fortunately it is easily cured using commercial preparations. It is important to remember that the medication works best on the free-swimming tomites. Therefore medication needs to be administered regularly (according to instructions on the bottle).

The white spot organism can be introduced through adding infected tap water to a tank, by introducing diseased fi sh, or by spreading the disease from an infected tank with a net or equipment. Since white spot can be easily introduced with infected tap water, it is a good practice to hold and age tap water for several days before use. The disease has been cured, experimentally, by putting fi sh in fast running water and simply washing all the free swimming tomites away before they re-infect the fi sh.

Discussion White spot is one disease that nearly all aquarists have heard of, and as such, is often incorrectly diagnosed. Inexperienced people call any white blemish, discolouration, or fungus patch, white spot. A microscope is the best way to make a positive diagnosis, although with experience, white spot can easily be identifi ed with the naked eye. Be prepared for fi sh to look worse before they get better. This occurs because most treatments cannot reach the parasites buried deep in the fi sh’s skin. So, the parasites must mature, leave the fi sh, and turn into free-swimming tomites before the treatment has an effect. Increasing temperature is an effective way of speeding up the life cycle and therefore speeding up the cure time.

Treatment Use Aquasonic Ichonex or any commercial white spot treatment according to instructions.

NOTE: Turn off activated carbon ﬁ lter, if in use, as it will remove medications on contact.

CAUTION: Scaleless ﬁ sh may be sensitive to some white spot remedies, therefore use treatment at half dose if unsure. Example of White Spot

TECHNICAL NOTES 38 WHITE SPOT DISEASE velvet disease of freshwater ﬁ sh

Velvet disease is caused by Oodinium pillularis, a dinoﬂ agellate parasite (or other Oodinium species) that is virtually invisible to the naked eye.

Symptoms First symptoms of velvet disease are usually slight variances in behaviour. Fish swim a little more stiffl y, are less active, and show an increase in respiration rate (gill pumping). The surface of the fi sh becomes coated by thousands of parasites resulting in the classic “velvet” symptom. Fish seem coated with fi ne golden pepper and, usually, fi ns look thickened. If left untreated fi sh become more lethargic, hang at the surface, lose condition and heavy mortalities occur. Secondary fungal and bacterial infections are uncommon.

Because the velvet parasite is not quite visible to the naked eye and occasionally infections remain completely localised to gills, positive diagnoses cannot be made without the aid of a microscope. At x100 or x 200 magniﬁ cations, velvet can be seen as dark, oval to pear shaped cells, which do not move.

Life Cycle The life cycle of Oodinium pillularis is similar to that of white spot. Once the parasite has matured on the fi sh, it drops off and falls to the substrate. Here it divides and produces up to several hundred offspring. Juveniles are propelled by a single fl agella and swim about in search of a host, which they must fi nd within a day or so or they perish. Successful parasites attach themselves to the host with fi laments that penetrate the skin.

Control Ensure, as far as possible, your source of live ﬁ sh is velvet disease free by buying from a reliable supplier.

In the event of an outbreak, quarantine the tank and take quick action with a “proven” treatment procedure (follow treatment instructions at the end of this article).

Discussion Velvet is a relatively common disease of fresh water ornamental ﬁ sh, and it is often mis-diagnosed. An untreated tank, in any establishment, can become an on going source of contamination causing problems for months.

Treatment Use any commercial velvet treatment, according to instructions.

Treatment Note Velvet has a reputation for being difﬁ cult to cure and even more difﬁ cult to eradicate from established aquariums. Repeated treatments are usually required.

in groups on the skin Oodinium pillularis

TECHNICAL NOTES VELVET DISEASE OF FRESHWATER FISH 39 anchor worm (Lernaea)

This disease is caused by copepods within the genus Lernaea. They are not worms, even though the adult female parasites are somewhat worm like in appearance.

Symptoms Infected fi sh develop stiff, worm-like protrusions between 10 to 20mm long on the body or occasionally on fi ns. Mouthparts of the parasite are embedded in the fi sh’s fl esh, often causing some ulceration. One pair of egg sacks are usually present at the protruding end of the female anchor worm.

Adult female

Life Cycle Female anchor worms produce hundreds of eggs in each egg sack. Larvae are free swimming and about 0.3 to 0.1mm long. After mating, only female parasites penetrate the ﬁ sh where they stay buried for only 7 days or so at tropical temperatures, or up to 3 months if temperature is below 15°C.

Control Anchor worm is a relatively common disease, of both pond cultured and wild ﬁ sh in Australia. Because of this it’s best not to introduce any ﬁ sh from the wild. In the event of an infection, quarantine the aquarium and treat according to instruction at the end of this article.

Discussion Anchor worm infections are more likely to occur on goldﬁ sh, pond cultured ﬁ sh, and wild-caught Australian natives.

Treatment Use Para-gone or any commercial anchor worm treatment according to instructions on the container.

Treatment Note Because the medication cannot reach young buried female parasites, treatment must be repeated several times depending on temperature.

At 25°C - 30°C treat 3 or 4 times 5 days apart At 20°C treat 2 or 3 times 12 days apart At 15°C treat 2 or 3 times 25 days apart

NOTE: Carry out a 50% water change between treatments.

TECHNICAL NOTES 40 ANCHOR WORM (LERNAEA) skin & gill ﬂ ukes

Skin fl ukes are common microscopic parasites of fi sh. They are often found on goldfi sh, causing many of the problems commonly encountered in aquarium and pet shops. There are two common types of fl ukes that cause disease:

Gill Flukes (Dactylogyrus) Skin Flukes (Gyrodactylus) Symptoms The only sure way of diagnosing fl ukes is with the aid of a microscope. A section of tail, gill, or scraping from the body reveals these tiny microscopic parasites. The normal response to skin parasites is for the fi sh to increase mucous secretion, in a bid to dislodge the parasites. This appears as a thickened slime coating over the body. Infected fi sh often start shimmying, develop clamped, cloudy or drooping fi ns, and scratch on the gravel and rocks.

Gill fl ukes usually attack gills, where the mucous secretion of the fi sh and the physical damage caused by fl ukes, severely interfere with the fi sh’s ability to take up oxygen from water, (to breathe). If infected fi sh are left untreated, the fl ukes cause so much damage to the protective skin coating that the fi sh eventually die.

Control It seems that fi sh under normal conditions usually have an adequate defence system to keep these parasites at a relatively harmless level. When fi sh are stressed by crowding or kept in an unsuitable environment, fl ukes multiply quickly and become a major problem.

Gill fl ukes are egg layers, and skin fl ukes are live bearers. Both types of fl ukes are able to spread from fi sh to fi sh, and are easily transferred from tank to tank by use of a common net. It is quite likely some species of fl ukes are host specifi c (only parasite one species of fi sh) however it is wise to assume cross contamination can occur.

Discussion Our investigations have shown this disease to be a major cause of goldfi sh losses in home aquariums and bowls. Infected goldfi sh may take weeks or months to die, and many outlets unknowingly sell these fi sh. It is a major industry concern, as high failure rates of beginner goldfi sh keepers discourage the progression to serious fi sh keeping.

Treatment Several commercial preparations are now available for treating ﬂ ukes. In recent years, some ﬂ ukes have become resistant to some treatment chemicals. It is therefore wise to stock a few different treatments that use different chemicals as the active ingredient.

TECHNICAL NOTES SKIN & GILL FLUKES 41 slimy skin disease

Slimy skin disease is a catch all phrase used to describe a symptom usually associated with ﬁ sh infected by a group of tiny microscopic external parasites.

Symptoms As with skin fl ukes, the only sure way of diagnosing these parasites is with the use of a microscope. The gills, fi ns, and body, are all usually infected when the parasites are present. Symptoms include - thickened, whitish-grey, slime coating; occasional sloughing, twitching and scraping. Fusion of gills causes increased breathing frequency. In the fi nal stages of the disease, fi sh hang at the surface, or lie at the bottom. Secondary fungal and bacterial infections are common.

Control These parasites are often associated with crowding of fi sh and water with high organic loads (polluted water). Keeping fi sh in an ideal environment is a way of avoiding this problem. The parasites can easily be spread through the use of contaminated nets. If infected fi sh are removed from an aquarium, it seems that all free swimming parasites will die off within a few days, when no host is present.

Discussion These three types of parasites can be found on goldfi sh as well as tropical fi sh. When examining a weakened fi sh it is not unusual to fi nd a mixed infection of these parasites as well as skin fl ukes.

TREATMENT – Use a commercial treatment Aquasonic Formalin and Malachite green has proven to be very affective.

CAUTION: Formalin and Malachite green is toxic if overdosed.

Alternative Treatment Try a long duration salt bath of 30gm (6 teaspoons) sodium chloride per 10 litres of water, plus a commercial fungus remedy. When ﬁ sh have recovered, (normally 2 or 3 days) carry out a 1/3 water change every day, for 3 to 4 days, to dilute medication.

NOTE: Salt at this concentration will kill most aquatic plants.

TECHNICAL NOTES 42 SLIMY SKIN DISEASE Columnaris disease (body and mouth rot)

Columnaris disease is usually caused by the bacteria Flexibacter columnaris, but may also be caused by a variety of bacteria.

Symptoms This is the most common bacterial disease encountered by professional aquarium fi sh handlers. It is contagious and in its early stage, quite diffi cult to diagnose. Some types of fi sh are particularly susceptible, e.g. female fi ghters, guppies, platys, swordtails, and to a lesser extent, mollies and rasboras. Diseased fi sh develop grey/white patches, usually at the base of the tail, at the tips of the fi ns, and on the back. Often a slimy white line appears around the mouth. The bacteria, after penetrating the protective slime coating, gain access to tissue beneath the skin where, if left untreated, they can cause enormous damage.

During the progress of the disease, fi sh become listless, lose their appetite and tend to hover at the surface near aeration. (Infected guppies in particular act this way.) The proliferation of bacteria over the gill fi laments, and the heavy production of mucus by the fi sh, contributes to impaired gill function and oxygen starvation. If appropriate treatment is not given, the entire contents of the aquarium may be lost within a few days.

Fish Showing Symptoms Of Columnaris Disease

Control The bacteria that cause this disease are present as normal ﬂ ora in waters all over the world. Under normal conditions the ﬁ sh’s immune system prevents invasion by the bacteria. Adverse conditions such as incorrect water quality, high organic load, low oxygen levels, poor diet (e.g. lack of vitamin C), excessive handling, or shipping stress, are all conditions that may lead to the development of this disease. Care should be taken not to transfer water, nets, plants etc, from the infected tank.

Discussion As in human and veterinary medicine, bacterial diseases are usually treated with antibiotics, which in Australia are classifi ed by the Department of Health as S4 drugs. This means they can only be supplied under prescription. Aquarium and pet shop owners should therefore use a veterinarian as a consultant, if they wish to acquire antibiotics for treating bacterial diseases of aquarium fi sh. Aquarium Industries Vet Services can be contacted by calling 1800 WECARE Tetracycline hydrochloride has been approved for use on ornamental fi sh. This drug does not need a prescription, yet at the same time is quite effective at preventing and treating columnaris disease.

General Treatment Columnaris bacteria, usually start off attached to the outer surface of ﬁ sh and therefore the disease is relatively easy to treat in the early stages.

Preventative Measures 1. Ensure water quality is right for the species of ﬁ sh; e.g. correct pH, general hardness, and water conditioner levels for live bearers etc. 2. Use any good quality commercial antibacterial product as a preventative whenever new “columnaris disease prone ﬁ sh” are purchased.

TECHNICAL NOTES COLUMNARIS DISEASE (BODY AND MOUTH ROT) 43 Columnaris disease (body and mouth rot)

Treatment Tetracycline There are several commercial aquarium products containing Tetracycline available now. Treated water may develop a brownish tinge after a day or two. Activated carbon ﬁ ltration and partial water changes should be used to clear the water again after ﬁ sh have recovered.

Alternative Treatment The antibiotic Doxycycline (Vibravet) at the rate of 5mg/litre is very effective but has a detrimental effect on biological ﬁ lters.

Notes: 1. Tetracycline has little or no ill effect on nitrifying bacteria living in the biological fi lter/gravel. 2. Columnaris disease is also a disease of cold water fi sh, including medakas and goldfi sh. The resistance of the fi sh to the disease is usually reduced as the temperature of the water increases, e.g. goldfi sh are much more prone to this disease when temperatures go above 18°C. 3. Infected fi sh usually lose their appetite and have a high oxygen requirement, so be careful not to pollute the aquarium water with uneaten food and ensure aeration is strong enough. 4. Other antibiotics such as Streptomycin and Doxycycline are often recommended in aquarium literature. These are effective but have a detrimental effect on biological fi lters, and as with virtually all antibiotics, must not be used without a prescription from a veterinarian.

TECHNICAL NOTES 44 COLUMNARIS DISEASE (BODY AND MOUTH ROT) neon disease

Neon diseases are mostly diseases of Neons. They can occasionally be seen in other species, although this is quite rare.

There Are Two “Neon Diseases” Enormous confusion exists over two quite different diseases; both called Neon Disease in the industry. This is why we have called the more economically important disease, neon splitting disease (or false neon disease). The other neon disease we prefer to call Plistophora, after the causative organism, Plistophora hyphessobryconis.

Neon Splitting Disease (False Neon Disease) The most common disease of neon tetras (Paracheirodon innesi) is bacterial neon splitting disease. The speciﬁ c bacterium that causes this disease is not known.

Symptoms Losses are often associated with stress of travel, or after fi sh have been moved into a new tank, especially if the water is fresh, hard and alkaline. A slightly raised, white mouldy looking patch develops, usually on the back, around the dorsal fi n. The gills may also be infl amed and swollen, with the gill plate protruding slightly. If untreated, the patch quickly develops into a deep lesion, and death soon follows. This disease can cause high losses, and spreads within the tank’s population rapidly. Early treatment is essential.

Control Neon splitting disease seems only to be a problem in commercial establishments. There have been very few reports of this disease in home aquaria. Attention to water quality is the single most important factor in controlling outbreaks. Mixing batches of neons should be avoided. If an outbreak occurs, use normal quarantine precautions to avoid its spread. This disease does not seem to be contagious to many other species. We have seen it in cardinals, and occasionally in giant danios, emperor tetras, glowlights and black neons.

Discussion Neons are very sensitive to adverse water conditions, and areas that have naturally occurring, hard, alkaline and mineral rich tap water, are notorious for having neon problems. Shopkeepers in such areas should alter their tap water to suit their neons, especially for newly received ﬁ sh. Once over the stress of transport, neons do acclimatize to local water conditions and one need not be as fussy. (See articles on pH, general hardness, and neons).

*Tip For Avoiding Problems Neons in their natural habitat live in water with a pH of about 5.0. Put newly arrived neons into a pH of between 5.5 – 6.0 and then gradually raise it over several days to just under 7.0.

Treatment Ensure water conditions are right for neons ﬁ rst. Use Doxycycline (Vibravet) at 5mg per litre. After 4 days change ½ the water, than repeat treatment if necessary

Alternative Treatment The antibiotic Doxycycline (Vibravet) at the rate of 5mg/litre is an effective treatment but it has a detrimental effect on the biological ﬁ lter.

TECHNICAL NOTES NEON DISEASE 45 neon disease

Plistophora Plistophora hyphessobryconis is an internal parasite that attacks muscle tissue. Pale patches develop inside fi sh, often causing part of the green line along the Neon’s side to pale or fade. The disease is slow to progress, and fi sh may live for months showing little or no sign of ill health. In the fi nal stages, emaciation usually precedes death. This is a slow, insidious disease that usually occurs due to lack of adequate disease controls. Unfortunately, there is no practical treatment. Infected fi sh should be destroyed; as the disease spreads when healthy fi sh eat infected corpses.

Comparison Of The Two Diseases The common symptom of both diseases is the development of a pale patch, usually in the area of the green line.

Neon Splitting Disease Plistophora Disease

Caused by bacteria Caused by sporozoan Spreads quickly within the population (causes epidemics) Slow to spread Very heavy losses (within days) Slow to cause losses (weeks or months) Responds to treatments Virtually incurable Currently a common disease

Neon Splitting Disease Plistophora

Spore ﬁ lled pansporoblasts of Plistophora hyphessibryconis in musculature

REMEMBER: As well as these two diseases, neons may also develop many others.

TECHNICAL NOTES 46 NEON DISEASE