T r e a t m e n t   a n d   M e t h o d o l o g y*

Method A1


Use:  Abdominal dropsy, furunculosis, bacterial fin rot, vibriosis, bacterial gill disease.

Action: Gram-positive bacteria, cocci, and spore bacilli: Gram-negative bacteria and cocci; acinomycetes, flexibacteria, spirochetes, rickettsias, and large viruses.  The drug can be stored cool or dry, for years.  Use as a long bath in a separate container.

Dosage:  40 mg per liter of water for 10 to 20 hours.  The drug can be dissolved in a small quantity of ethyl alcohol before adding it to the treatment tank.  During treatment, run the filter over clean absorbent or raw cotton or foam filter material.  Check on the fish and the condition of the water often.  If the water turns turbid, take the fish out and, if need be, transfer them to freshly mixed solution  Chloramphenicol can be mixed into the feed according to method B5.  Since it tolerates temperatures up to 100 degrees C, it can be stirred in at a temp of 80 degrees C.

Dosage in feed:  500 mg per 100 g feed, given twice daily for three days.

Method A2

Combination treatment for columnaris disease with chloramphenicol + acriflavin (trypaflavin).  Carry out treatment as in A1.

Dosage: 4 ml stock solution of acriflavin (see method C1) to a liter of aquarium water, to which is added 40 mg chloramphenicol per liter water.  Length of treatment is 12 hours.

Method A3

Neomycin Sulfate

Use:  External bacterial diseases such as fin rot, skin lesions, and the new discus disease.

Spectrum of action:  Gram-negative bacteria and cocci.  Administer as a long bath in a separate container and filter over clean raw cotton or foam filter material

Dosage:  2 g to 100 liters of water for three days.  In rare cases, sensitive fish can be poisoned.

Dosage in feed:  250 mg mixed into 100 g feed according to method B5.  Feed three times a day at four-hour intervals for three days.  Maximal temperature when mixing is 40 degrees C.  This method is useless for infections of most internal organs and is used only for intestinal infections.  Combination with nitrofurantoin (see method C21) at the above dosage can be effective in the new disease of discus.  The precondition is that the usually present secondary parasites be controlled first.  Transfer the fish to clean freshly prepared water before treatment.  The fish remain in the bath for three to five days, then they are transferred to fresh water.  A follow-up treatment with nitrofurantoin can be carried out for six to ten days, but is usually not necessary.

Method A4

Combisonum eye ointment containing neomycin (see A3)

Combisonum is the drug of choice when fish have injured themselves.  It protects against bacterial infection and fosters healing.  Take the fish out of the aquarium (quarantine tank) every day and wrap it in a wet towel.  Dry the wound carefully with blotter paper, which also removes any dead tissue.  Then apply Combisonum.  When the edges of the wound begin to close over, apply treatment only every second or third day.  As prophylaxis, a fungicidal ointment can be applied every third day or a mycostatic agent added to the water (method C12 or C17d).

Method A5

Tetracycline HCl

Use:  Abdominal dropsy, vibriosis

Spectrum of actions:  Gram-positive cocci and bacteria, Gram-negative cocci, bacteria, actinomycetes, spirochetes, and large viruses.  This drug can be given as a permanent bath at Dosage A (see below) in an already setup aquarium, with filtration over clean raw cotton or foam filter material.  The water becomes colored and several plant species will be damaged, so the use of a separate container is recommended.

Dosage A: 1 g to 100 liters of water for four days.

Dosage B:  100 mg per 1 liter of water for 24 hours (only in a separate container).  In the feed described under method B5, 750 mg tetracycline HCl is mixed with 100 g feed and then administered two times daily at six-hour intervals for seven days.  Stir in at a temperature of 40 degrees C.

Method A6

Chlortetracycline, Oxytetracyclin (contained in Aureomycin and Terracycin-Hen)

Use:  Usage, effect, and dosage in regard to the tetracyclin content are equivalent to A5.  Because of the other ingredients in it, Terramycin is used only in feedstuffs.  Doxyxycline 100 is likewise a tetracyclin.  It is known as Vibramycin

Dosage:  The content of one capsule to 20 liters of water for two to four days.

Method B1

Heat Treatment

The raising of temperature as therapy has a long history.  It should be raised slowly and not more than 1 degree C hourly.  The rational of this therapy is to create an environment in which the  pathogen is no longer viable or able to reproduce.  Not all species of fish can tolerated higher temperatures.  Chemical treatment is sometimes easier of the fish.  Heat therapy can be applied for the following pathogens:

    Costia spp.:  33 Degrees C for four days.

     Ichthyophthirius spp.:  33 degrees C for ten days

     Oodinium spp.:  33-34 degrees C for 24 to 36 hours.  Absolutely clean water and good aeration are essential.

If the fish do not seem to feel well and this is not due to polluted water or chemical causes, an increase in temperature of 3 degrees C for two or three days can have a very positive effect.  Resistance against infections is increased because more antibodies are formed.  For discus the temperature can be raised even as high as 35 degrees C.  Greater increases in temperature, however, burden the fish's metabolism too severely, so that stress increases and resistance again drops.


Method B2

Transfer method

With this method, the life cycle of Ichthyophthirius can be interrupted, thus preventing spread of the disease.  The method takes time and effort, requiring five containers.  Every 12 hours the fish are transferred to a new container.  The cysts that drop off release their swarmer cells only after the fish have already been transferred to the next container.  When the fish "recycle" on the sixth day to their first container, the swarmer cells have already died.  Then temperature in all containers should be 25 degrees C.  If the treatment lasts 23 days, you can be rather certain that the fish are free of "ich."  The daily handling for transfer, however, stresses the fish quite severely.

Method B3

Screening method

This method is appropriate for all parasites that do not develop any motile swarmer cells or larvae.  It is used mainly in the breeding of schools of fish.  In the breeding tanks, a screen or grid is installed at a height of 2 to 5 cm above the bottom.  The mesh is too small for the fish, but allows the eggs of the parasites to fall through along with the fecal matter, thus dropping them out of the fish's reach.  The emerging larvae die.  The problem, however, is vacuuming out the mulm that collects under the screen.

Method B4

Vitaminized feed

You can easily produce your own vitaminized feed that contains all the important vitamins and trace elements.  Scrape some beefheart onto a plate and add half as much of finely shredded deep-frozen spinach.  Spread it all out into a layer about 3 to 5 mm thick.  Then sprinkle enough vitamin powder over it until the whole surface is whitish (see also method C27).

The use of liquid vitamins is ineffective because it does not adhere to the feed.  Spread the same amount of brewer's yeast powder (from a health food store) evenly over the feed and leave it there until the beef-heart and spinach thaw out (about 15 minutes).  Then mix it all together, kneading it well, and feed it right to the fish.  Finely grated carrots can substitute for the spinach.

When using Osspulvit-N, Neocalcit tablets, and Calcipot D3, vitamins missing from these products can be provided with VMP tablets (Pfizer) by pounding the tablets and sprinkling the powder, as described above, on the spread-out feed patty.

Method B5

Recipe for preparation of medicinal feed

Prepare a mash of two-thirds beef-heart or lean beef and one-third spinach.  Both ingredients must be minced small enough to be ingested by small fish.  After thorough mixing, 50-gram portions are frozen in small plastic containers or bags then later thawed as needed.

Now, to a small tin can, add 50 ml cold water and 1 gram powdered agar.  A tiny amount of red food dye makes the feed more appetizing, as does some Maggi (brand name of a German herbal or condiment additive for food seasoning), not more than needed for a cup of coup.  Stir with a small fork while heating the can of mix in a water bath until the agar dissolves and the solution thickens.  At about 80 degrees C, stir in the 50 g beef mash in small portions without letting the temperature drop significantly.  When all the beef mash is stirred in, remove the tin can from the water bath and let it cool slowly.  Depending upon its heat stability, the medication is stirred into the hot, liquid feed or added just before solidification at about 40-50 degrees C (follow the instructions under methods of treatment).  Many antibiotics do not tolerate any heat, so the feed must be cooled down quickly (in a refrigerator to 2-5 degrees C) after stirring in the active ingredient.  Do not let it freeze, or the agar again liquefies.  The finished feed has a solid, rubbery consistency and fish like to eat it once they become accustomed to it.  It can be kept three days in a refrigerator at 2 to 5 degrees C.

For feeding, cut the mass into mouth-sized fits that will remain solid in the aquarium at up to a temperature of 28 degrees C (82 F).  After 12 hours at the most, all uneaten food must be removed from the tank, otherwise it will become moldy.  Any antibiotics mixed into the feed soon lose their efficacy, therefore do not give more medicated feed than can be eaten in an hour.

Method C1

Acriflavin (Trypaflavin)

Use:  Skin turbidity or clouding, mouth rot, fin rot, and disinfection of small wounds.

Spectrum of Action: Costia spp.,  Chilodonella spp.,   Trichodina spp.,  Trichodinella spp., flexibacteria, fin and skin turbidity or cloudiness.

Both names refer to the same drub.  It dyes intensely.  Acriflavin can be put into the completely set up aquarium but severely damages plants.  The filter substrate should be cleaned before addition of the drug.  After the treatment, filter over activated charcoal to remove the drug.

Stock Solution:  1 g to 1 liter of water.

Dosage A:  1 ml stock solution to each liter of aquarium water to prevent infections.

Dosage B:  3 ml stock solution to each liter of water for four days to help against infections in the early stage.

Dosage C:  5 ml stock solutions to each liter water in a separate container for two to four days against Columnaris spp.,  Costia spp.,  Trichodina spp.,  and Chilodonella spp.

Dosage D:  10 ml stock solution to each liter water in a separate container for 20 days ( against Ichthyophthirius spp.) or for 10 days (against Oodinium spp.).  Caution:  Many fish do not tolerate this dosage.

Method C2


Leeches attached to fish can be removed by pressing an alcohol soaked cotton swab briefly on the leech.  The fish must be lifted out of the water for this treatment.

Method C3

Basic (or alkaline) brilliant green

This dye comes in various fish medication preparations available at pet shops, and these are more convenient to use than the pure brilliant green.

Use:  Skin turbidity (or cloudiness), fin rot, gill rot, skin fungus, mouth fungus.

Spectrum of Action:  Gram-positive bacteria, skin fungi, and protozoa.

Carry out the treatment in a separate tank, with the water filtered over clean absorbent cotton or foam filter material.  This treatment is toxic to many fish.

Stock solution:  1 g to each liter water.  Keep in a brown or amber bottle.

Dosage A:  2 ml stock solution to 12.5 liters water for 24 hours, then total change of water, or transfer the fish to another container.  This treatment can be repeated on the third day.  For bacterial infections of the skin.

Dosage B:  2ml stock solution to 15 liters of water.  Bathe the fish in this solution four hours at a time on three successive days.  The working solution must be freshly made for every treatment (i.e., add stock solution to fresh water each time).  Used for parasites and fungi

Method C4

Quinine Sulfate, quinine HCl

Use:  Freshwater Oodinium

Dosage: 1 g quinine to 100 liters water as a continuous bath for three days.  Quinine poisons fish that are sensitive to it and lower animals do not tolerate it very well.  Quinine HCl is preferred over quinine sulfate.  Although quinine decomposes after some time in water, it is better to filter it out over activated charcoal after the treatment.  It is safer to treat the fish in a separate small tank and then treat the aquarium by itself.  That way no fish will die when the water is poured into the aquarium.  Afterward, change all the water.  Transfer the fish to separate treatment tanks containing freshly prepared medication if the aquarium water becomes turbid.

Method C5

Concurat L 10%

This is a broad-spectrum verifuge for cattle, sheep, goats, swine, and poultry.  Because of its sweet taste, it must be kept out of the reach of children.

Use:  Intestinal nematodes

Dosage A:  Dissolve 2 g Concurat in 1 liter of water.  Soak living bloodworms in this solution until the first larvae die, then immediately feed the still living ones to the fish.

Dosage B:  Mix 1 g Concurat into 100 g feed.  Stir into feed made by method B5 at 50 degrees C.  Give once daily over five days.

Method C6

Flubendazol & acetone or DMSO flubenol 5%

Flubendazol is a solvent used for gill, skin and intestinal worms.  Since the active ingredient is insoluble in water, it has to be first dissolved in an organic solvent.  Dimethylsulfoxide (DMSO) was used in recent years.  It is very toxic and should not come in contact with unprotected human skin.  In no case should children get hold of it.  Fish tolerate it well when no other chemicals or drugs are in the water.  Even water preparation substances can become toxic in the presence of DMSO.  The tank or breeding facilities must be in an absolutely clean condition.  High levels of nitrite or ammonia, in the presence of DMSO, can become lethal to fish.  Rinsing out the filter material and changing a large portion of the water beforehand has a  good effect.  DMSO also cause an unpleasant tank odor for weeks.  Since treatment also kills gill worm eggs, the treatment does not have to be repeated.  Because of all of the above risks associated with DMAS, it should not be used by aquarists any longer.

Acetone has been used very successfully since 1988 as a well tolerated solvent for flubendazol.  All gill and intestinal worms as well as their eggs are destroyed.  Only at 100x normal dosage does acetone become toxic to fish.  It does no leave any unpleasant odors in the vicinity of the tank.  Feeding with flubenol 5% in feed mix B5 destroys the intestinal worms, but re-infection is possible when fish pick up eggs from the bottom.

Dosage A:  For each 100 liters of tank water, put 200 mg flubenol 5% in a small glass (do not use plastic) and then add 5 ml acetone or DMSO.  After agitating several minutes, distribute the milky suspension over the surface of the water.  After five to eight days begin to remove the medication by water changes.  The water can become slightly turbid.  Aerate the water well during treatment.  Bacterial overgrowth may occur in many cases, causing turbidity  and oxygen-depletion symptoms in the fish.  An immediate major water change is necessary.

Dosage B:  Add 100 mg flubenol 5% to 100 g feed mix B5.  Give it five times every second day.  On those days feed only once with the regular diet.  Microscopic monitoring of the treatment will not reveal nay results for ten days, but after this time the worms begin to die.  That is expected because flubenol 5% blocks the resorption of certain nutrients for the intestine, thus starving the worms.  That takes about eight days for gill worms, or Oxyurida about ten days, and for Capillaria about 15 days.  In the female worms, however, damage to the egg walls can be seen as soon as the second day of treatment.  They seem malformed and burst when expelled.  Therefore there are no worm eggs visible in the feces or on the gills by the third day of treatment

Method C7

Formalin (35 to 45% solutions of formaldehyde)

Formalin is highly toxic and carcinogenic

Use:  Ectoparasites on skin and gills.  Do not use if the fish have large-area skin wounds (Costia and "ich" in advanced stage).

Spectrum of action:  Gill and skin worms, chilodonella spp.,  Trichondina spp.

Dosage:  Short bath with 2 to 4 ml formalin in 10 liters of water for 30 minutes in a separate tank.

Observe the fish well.  Stop treatment if the fish lose equilibrium.  Many fish tolerate formalin very poorly.  For egg-laying gill worms, the treatment can be repeated in three days.  After treatment transfer the fish to a parasite-free tank.  For Brooklynell hostillis, Blasiola recommends 2.6 ml formalin to 10 liters of seawater in a separate tank.


Method C8


Use:  Whit, slimy feces.

Spectrum of action:  Intestinal flaggellates and cillates.

Gabbrocol has proven itself against flagellates and cilates.  It can be used as a long bath or in the feed make by method B5.

A Gabbrocal bath is problematical because the vehicle that carries the active ingredient is glucose.  Treatment must take place only in an empty glass tank with vigorous aeration and filtration over clean absorbent cotton or foam filter material.  Glucose causes heavy turbidity in the water because of bacterial reproduction.  After about 18 hours an oxygen deficiency often occurs, causing the fish to have difficulty breathing and then suffocating.  For that reason even robust fish should not, as a rule, remain longer that 18 hours in the solution.

The fish must be transferred to clean water, at the latest when the bath water becomes turbid.  This amount of time is adequate for the treatment.  If you want to be extra certain, then transfer the fish after 12 hours to another aquarium containing freshly added Gabbrocol solution.  Bacterial proliferation and thus water turbidity can be delayed by using distilled water or boiled tap water.  The treatment tanks must be thoroughly washed out with hot water.

Dosage:  Dissolve 5 g Gabbrocol (one bag) in 30 liters of water.  Let the fish bathe in this for 18 hours.  In severe cases, the bath can be repeated in another tank containing freshly added solution.

Dosage in feed:  Mix 2 g Gabbrocol into 100 g feed (see method B5) at 40 degrees C and feed for three days.  In severe cases, feed the mix until the white feces disappear, at which point continue the treatment for another three days.

Method C9

Griseofulvin, Fulvicin tablets (500 mg)

Use:  Mouth fungus, skin fungus, gill rot, and other mycoses.

Spectrum of action:  Almost all external fungi on fish.  Since usually only a few fish are affected, prepare the long bath in a separate tank.

Dosage:  10 mg to 1 liter, or a 500 mg tablet in 50 liters of water.

Pound the tablets into powder an pre-dissolve in some warm water.  Three days after the hyphae disappear, the treatment can be stopped.  If the aquarium is already set up, this treatment may damage the plants.  After treatment, change half of the water and filter out the rest of the drug over activated charcoal.

Method C10

Potassium iodide and iodine

Use:  Thyroid swelling.

Benign thyroid tumors can be treated with these chemicals, showing improvement only after two to four weeks, at which time the swelling or tumor slowly regresses.  Carry out the treatment in the aquarium.  Do not filter over charcoal.

Stock solution:  0.5 g iodine and 5 g potassium iodide dissolved in 100 ml water.

Dosage:  With a pipette, add 1 drop of the stock solution to every 5 liters of aquarium water.  More precisely, add 1 ml stock solution to 50 liters of aquarium water.  The appropriate dosage is re-added after every water change.

Method C11

Potassium permanganate

Use:  Very heavy infestation with the parasites listed below.

Spectrum of action:  Trichonina spp.,  Argulus spp.,  gill worms, Saproleginia spp.

Treat the fish with a short (immersion) bath of 30-45 seconds in a separate container.  The dosage that causes toxicity is close to the level needed to kill the parasites, so this treatment should be used only for emergencies.  Treatment according to method C18 is easier on the fish.  The effect of medication is significantly weaker in organically polluted water than it is in clean water.

Method C12

Nacl (kitchen, rock, mineral, or sea salt)

Salt is most certainly the oldest medication used in fish diseases.

Use:  Incipient skin and fin cloudiness (or turbidity and mild infestation with the parasites listed below).

Spectrum of action:  Costia spp.,  Chilodonella spp.,  Trichodina spp.,  fungi, leeches.  For mild cases, salt is used in long and short baths.

Dosage A:  (short bath):  15-20 g for each liter of water.  Bath lasts 10 to 45 minutes.

Dosage B:  (long bath):  1 g to each 12.5 liters of water in the aquarium for soft-water fish.  3 g to each 10 liters of water for hard-water fish.  Intermediate values have to be estimated.  After five days, the salt content can be reduced by changing the water.

Plants can be damaged starting at a salt concentration of 2 grams per 10 liters of aquarium water.  We can prepare our own physiological saline for microscopy by dissolving 6.4 g of salt in 1 liter of water.

Method C13

Copper sulfate, CuSo4-5 H2o (blue crystals)

Use:  Oodinium, algae, fungi, and mixed infections with the following listed below.

Spectrum of action:  Costia spp.,  Saprolegnia spp.,  Branchiomyces, Oodinium, Algae, and Gyrodactylus

Stock solution:  1 g copper sulfate and 0.25 g citric acid to 1 liter of distilled water.

Dosage:  12.5 ml to 10 liters of aquarium water for ten days.  Administer half of this on days three, five, and seven.

Test reagents for copper have been available for some time now among the diagnostic sets for water chemistry.  During treatment, the copper content of the water should not drop below 0.12 mg/L and not rise over 0.18 mg/L (using the Aqua Merck copper test no. 14651, Duplatest CU).  Test every other day and add any missing copper (1 ml stock solution=1 mg CuSO4).  Lower animals do not tolerate the treatment.  They must either be removed from the aquarium until the copper level again drops below 0.3 mg/L, or else the fish must be transferred to a spacious glass tank and treated there.  Filter over clean cotton or foam filter material.  For fungi and algae, the affected fish can be treated in a short bath of 1 gram of copper sulfate to 10 liters of water for 10 to 20 minutes.  Plants may be damaged.  Freshwater must first be hardened to at least 10 degrees DH before the treatment begins.

Method C14

Combination treatment for Cryptocaryon

Stock solution:  1 g copper sulfate + 2 g methylene blue + 0.25 g citric acid per 1 liter distilled water.  Carry out the treatment in a separate container.  Lower animals do not tolerate the treatment.

Dosage:  12.5 ml stock solutions to 10 liters water.  Half the dosage on days four and eight.  It is better to keep the copper level between 0.15 and 0.2 mg/Liter.  During treatment, filter over cotton or clean foam filter material.

Method C15

Combination treatment for Cryptocaryon (according to G.C. Blasiola, Aquarien Magazine, 1/81, page 14, Stuttgart, Germany)

Treatment involves two steps.  First, the fish are bathed in a short bath (one hour) containing 4 mg copper sulfate + 2.2 ml formalin (37%) to 10 liters seawater in a separate container.  Then they are transferred to a long bath containing 20 mg copper per 100 liters sea water.  The treatment must last ten days.  The short bath can be repeated at 48-hour intervals.

Method C16

Malachite green oxalate

Use: Ich, other skin protozoans, skin cloudiness or turbidity, and skin fungus.

Spectrum of action:  Ichthyopththirius spp.,  Trichodina spp.,  Chilodonella spp.,  Saprolegnia spp.,

The solution is stable only as long as it is kept cool and away from light.  Do not keep malachite green with edibles in the refrigerator because it is highly toxic and carcinogenic.  Pet shops stock malachite green preparations, and only when these do not work should the pure substance ever be used.

Dosage A:  6 ml of stock solution to 100 liters of aquarium water.  Give half the dosage on days three, six, and nine.  After 12 days, change a third of the water.  Any water changes needed during treatment must be redosed at the initial strength.

Aeration should be provided during treatment.  Malachite green is an intense pigment, and stains can be removed only with difficulty.  As a rule, even sensitive fish tolerate this dosage.  In water with a heavy organic burden, or in the presence of an active biological filter, the dosage may have to be increased.  However, do not exceed a dosage of 15 ml stock solution to 100 liters of aquarium water.  If the bath is prepared in a quarantine tank with very pure water and without an already broken-in filter, sensitive fish may not tolerate Dosage A under some circumstances.  That is because malachite green is broken down slower in hygienic tanks than it is in tanks with bottom matter and filter.  In such tanks the dosage is 4 ml stock solution to 100 liters of aquarium water and then followed up with 2 ml on days four, eight, and 12.

Dosage B:  According to G. Blasiola (Aquarien Magazin, 9/83m oage 477, Stuttgart, Germany), 13-15 mg/100 liters of sea water is effective against Brooklynella spp.  Treatment is given in a separate tank with filtration over cotton and good aeration for three to four days.  It is possible that the above dosage in freshly prepared sea water will not be tolerated.


Method C18

Metriforate, Masoten, Neguvon 100% trichlorphon

Use:  Skin and gill ectoparasites

Spectrum of action:  Trichodina spp.,  Argulus spp.,  Ergasilus spp.,  Lernaea spp.,  Dactylogyrus spp.,  Gyrodactylus spp.

Masoten is very toxic and acts vigorously on parasitic crustaceans and skin and gill worms.  It is significantly more effective as a long bath than it is as a short one.  At higher concentrations, from 28 degrees C up it is toxic to many species of fish.  Large species tolerate it better than do smaller ones.  Characins and catfish are particularly sensitive.  It has been repeatedly claimed Masoten makes fish infertile.  That is wrong.  Healthy progeny have repeatedly been bred from fish that were treated with high doses of Masoten (3 mg/L for three days).

Treatment can be carried out in the aquarium.  Only very dry powder (which looks slightly bluish) can be used; if it forms clumps, then it is unusable.  Masoten stored in apparently tightly sealed screw-top jars loses its effect over several months and becomes more toxic.  Tests have shown that this loss of effectiveness is associated with the ability to absorb atmospheric humidity.  The greater the moisture absorbed, the less the effect on gill worms and the greater the toxicity to fish.  Newly purchased Masoten is significantly tolerated better by all fish than is the stored product This aging process can be delayed by immediately repacking freshly purchased Masoten into tightly closing vials and then storing these, along with a desiccant, in larger glass containers such as jars, or the vials can be sealed in plastic bags.  Blue silica gel is an ideal desiccant, the blue granules losing their color when maximum moisture has been absorbed.  The gel can be regenerated by spreading it on a tin baking sheet and heating for about 15 minutes at 105 to 110 degrees C.  When the moisture is driven off, it turns blue again.  This can be done for years.

The quantities give here refer to newly purchased Masoten (assuming, or course, the source's stock is stored properly).  For Neguvon, multiply the quantities given by a factor of 0.8.

Stock Solution:  1 g Masoten to 1 liter water.  The solution must be used immediately because it is not stable.  Residues must not be dumped into the sewage line before they are neutralized by raising the pH above 12 with sodium hydroxide for two hours.

Dosage A:  100 ml stock solution to 100 liters aquarium water.  This concentration is tolerated well by almost all fish if the temperature treatment lasts three days, after which at least 50% of the water is changed.  The residual medication is filtered out over activated charcoal.

Dosage B:  1 g Masoten to 10 liters water as a short bath at 25 degrees C, pH 6 to 7, for one hour in a separate container. 

The method with Dosage A (above is better for controlling live bearing gill and skin worms.  With egg-laying Dactylogyrus species treatment is not so simple because the eggs can tolerate high levels of Masoten.  With the treatment recommendations described here, a whole population of fish can be freed of gill worms, a method particularly suited to breeding tanks that are free of bottom landscaping and decorations.

Dosage C:  The fish are treated according to Dosage A for three days in their aquarium.  Then all are caught and transferred to a parasite-free tank.  The original tank can then be washed out, the tubing and filter rinsed, the filter material washed and boiled for half an hour or disinfected with a formalin solution.  The aquarium is left at least three days to dry out.  On day eight following the start of treatment, Dosage A is begun in the second tank and continued for three days.  Mean while, the first aquarium is refilled with water and the filtration system started up.  Following the bath in the second tank, the fish can be returned to their own tank on day 11.  The filter needs a run-in time of at least three to six weeks.  The temperature cannot go above 25 degrees C throughout the whole treatment process.  Only at this temperature is there any guarantee that the larvae that hatched following the first treatment have not developed into sexually mature worms by the start of the second course of treatment.

This method does not effect a permanent cure because some of the Dactylogyrus eggs survive weeks or even months at the bottom of the aquarium before they develop further.  In this case, method C6 (flubendazol) is significantly simpler and easier on the fish, and it provides the absolute assurance that no more gill worms will appear after just one treatment.

In general, Masoten should not be used without careful consideration; many fatalities have indicated that handling this drub is not without its problems.  Outdated and highly toxic stocks are often used.  Its toxicity varies according to fish species and water characteristics; it increases as treatment duration lengthens.  High doses are usually tolerated well during the first 24 hours.  In no case should fish be put into used solutions or into solutions that are several hours old!  Masoten must be administered fresh each time.  The residual stock solution must be immediately neutralized with sodium hydroxide and discarded

Method C19

Metronidazole, flagyl (250 mg)

Use:  Flagellate infections in the intestine and organs.

Spectrum of action:  Hexamita spp.,  Sironnucleus spp.,  Trichomonas spp.,  Protoopalina spp.,  it does not help against worms.

Flagyl is used as a long bath in the already setup aquarium.  The tablets are crushed and first dissolved in lukewarm water, then distributed over the surface of the water in the aquarium.  The temperature can be raised to 30-33 degrees C to support the treatment.

Dosage:  250 mg (one tablet) to 50 liters of aquarium water.  After three days, change one-third of the water and gradually lower the temperature.  Filter over activated charcoal to remove the drug from the water.  Sensitive plants may be affected for a while.

Dosage in feed:  Crush a 250 mg tablet of flagyl into powder and, at 50 degrees C, mix it into the feed prepared by method B5.  Administer it morning and evening for six days.


Method C20

MS-222 (Tricaine), amino-benzoic acid ethyl ester methansulfonate

MS-222 is one of the best proven fish anesthetics.  It also acts on many lower animals and is used in microscopy to tranquilize microorganisms.  It's effect on fish attenuates with increasing water hardness.

Dosage A: (to tranquilize fish for travel):  10 mg per liter of water.

Dosage B:  (to anethetize fish when taking smears):  From 50 to 130 mg per liter of water, depending upon size of fish (Reichenbach-Klinke, 1980).  Transfer the fish to fresh water after 15 minutes at the very latest and let it recuperate there for another 15 minutes.

Dosage C:  (to sacrifice fish):  1 g to 1 liter water will euthanize in 10 minutes.

Method C21

Nitrofurantoin (gelatin capsules each containing 100 mg active ingredient)

Use:  Turbid (or cloudy fins) and fin rot (bath), external bacterial infections, prevent spread of abdominal dropsy, bacterial infection of kidney, vibriosis.

Spectrum of action:  Some Gram-positive bacteria, pseudomonas spp.,  Aeromonas spp.,  Vibrio spp.

If bacterially infected fish are transferred out of the aquarium and into a quarantine tank, then the remaining fish can be treated prophylactically with nitrofurantoin.  This medication can be administered in the aquarium if the filter material is first cleaned off and the bottom mulm aspirated out of the tank.  Activated charcoal must be removed from the filter.

Dosage:  Add the content of one nitrofurantoin capsule to 30-40 liters of aquarium water.  The capsule halves can be easily pulled apart to reach the ingredients, which are dissolved in a beaker of warm water and poured along with any undissolved residue into the aquarium being treated.  The long bath lasts 15 days.  Afterward, change a large portion of the water and filter it over charcoal.

Dosage in feed:  Add 300 mg pulverized nitrofurantoin (the contents of three capsule) to 200 g of the feed made by method B5 and administer morning and evening for nine days.

Method C22

Furazolidone (1 g cachet or envelope containing 300 mg active ingredient and 700 mg glucose)

This drug is cheap but can only be administered in feed.  The active ingredient is available only in 500 g packages, thus is relatively expensive.  Pure furazolidone can be given alone, without other substances, as a short bath.

Use:  Pseudomonas spp.,  Aeromonas spp.,  Vibrio spp.,  Trichomonas spp.,  and many coccidia.

Dosage in feed: Add, at 50-55 degrees C, 300 mg furazolizone to 100 g of feed made according to method B5 and feed morning and evening for six days.

Dosage for long bath:  500 mg pure furazolidone to 100 liters water in separate tank.  Do not filter over charcoal.   Change 40 to 50% of the water after three days.  Residual medication can be removed from the water by filtration over activated charcoal.

Method C23

Nystatin ointment

The ointment base consists of liquid polyethylene and liquid parafin, and it adheres particularly well to skin and mucosa

Use:  Fungal infections of skin, and prophylaxis for wounds.

Spectrum of action:  Fungi.

Lift the fish out of the water, carefully use blotting or filter paper to dry off the affected area, and then apply Nystatin ointment.

Duration of treatment:  One to two times daily until the fungal hyphae disappear, the wound closes, or new skin forms.

Method C24

Piperazine citrate

Use:  Intestinal worms.

Spectrum of action:  Thorny-headed worms, tapeworms, trematodes.

Piperazine citrate must be administered with feed so that it can act directly in the gut.  Since it is heat-stable, it can be mixed into the hot feed (prepared by method B5) at 80 degrees C.

Dosage:  Mix 600 mg piperazine citrate into 100/g feed (made by method B5 and feed once morning and evening on days one and eight.

Method C25

Sulfonamides, sulfathiazole

Sulfonamides are available from several manufacturers and under various trade names.

Use:  Internal bacterial infections.

Spectrum of action:  Actinomycetes, cocci, and many Gram-positive and a few Gram-negative bacteria.  Pseudomonas spp.,  flexibacteria, corynebacteria.

Since sulfonamides pass well from the gut to the blood, mixing it into the feed is its most effective application.  It is the drug of choice particularly in infections of the internal organs caused by the above organisms.

Dosage:  Mix 300 mg sulfathiazole into 100 g of the feed prepared by method B5.  The temperature should be 60 degrees C.  Administer the feed morning and evening for three days.

The poor solubility of the drug makes its use difficult in a long bath.  It is given in a separate container.  First dissolve the weighed amount of medication in warm (up to 60 degrees C) water in a closed vessel by agitating it for a minute.  Caution:  Since the enclosed air sharply expands in the closed vessel, it can explode! After the first shake, let the excess air escape.  After shaking, distribute it over the surface of the water in the treatment tank, which should not contain a filter, otherwise it would filter out the finely suspended sulfa drug.  To prevent it from settling out on the bottom, the water has to be kept vigorously circulating with a power head.

Method C26


Use: Bacterial and coccal infections of internal organs and blood.

Spectrum of action:  Staphylococci, hemolytic streptococci, pneumococci, Escherichia coli, enterococci, Proteus, Hemophilus influenzae, Salmonella, Shingella.

Combining trimetoprim with a sulfonamide offers a significant improvement in efficacy.  There are ready-made combinations available of trimethoprim and sulfamethoxazole in optimal proportions.  Since pathogens develop resistance very rapidly, the medication should be used only once every six months.

Commercially available preparations include:  Drylin, Eusaprim, Borgal solution (7.5%), and Cotrimstada-forte.  Drylin and Eusaprim are older preparations with low concentrations of active ingredient.  Today the most commonly used preparations or Bogai and Cotrimstada-forte.

Dosage:  1 table Cotrimstada-forte to 80 liters aquarium water for three to five days.  The filter cannot contain any charcoal; the filter floss has to be washed out thoroughly before administration of the drug.

15 ml Borgal solution to 100 liters water.  

For injection, calculate 2 ml Borgal solution (7.5%) per 200 g body weight.  A second injection can be given if necessary after 48 hours.  The injection is given intraperitoneally.

Only veterinarians and other experts should immunize or vaccinate fish.

Method C27

Vitamin preparations

Commercially available preparations for aquarists bind the vitamins to water-insoluble powder or oil to prevent their volatilization and loss and to facilitate their adherence to the feed particles until the fish ingests them.  It is important that they also include calcium and phosphorus to cure hole-in-the-head disease once the cause is removed.  Many other substances and trace elements have a positive influence on the health and color of fish.  Preparations that contain vitamins dissolved in water (aqueous solutions) are not very effective since they become dispersed in the aquarium water and are quickly decomposed.

Mix 500 mg vitamin powder into 100 g feed, which should to be fed to healthy fish more than twice a week.  It can be given to sick fish, though, four to five times a week.  Once these fish recover, the dosage is reduced to the normal one.

Excessive feeding of vitamins to fish causes signs and symptoms of disease.  When using Osspulvit-N or Calcipot in feed prepared according to methods B4 and B5, any missing vitamins or minerals must be replaced by other preparations.  The use of pulverized VMP tablets (Pfizer) is a possibility.

Method C28

Colon-A adhesive ointment

This ointment possesses outstanding characteristics of adherence to skin and mucus, which must be dried off first (as described in Method C23).  It is used for wounds and skin infections by applying it as a layer of ointment over the affected areas.  The active ingredient is anti-inflammatory, which means that even extensive skin wounds can be covered with it.  If necessary, powdered antibiotics, sulfonamides, or antimycotic (antifungal) agents can be mixed into the ointment.

Dosage:  Work the powdered active ingredient (5% by volume) into the ointment (95%).

Method C29

Hydrogen peroxide (3%)

In addition to disinfection, hydrogen peroxide can also be used to rapidly increase oxygen in aquarium water.  It decomposes into water by liberating pure oxygen.

Add 25 ml of 3% hydrogen peroxide to 100 liters of aquarium water (Krause, 1985).  In no case can the dosage be given a second time.  Over dosage with oxygen would corrode the gills and skin of the fish, resulting in their death.  If the fish do not breathe easier within several minutes following dosage, then the lack of oxygen has another cause for example, gill parasites)

Method D1

Potassium permanganate

Potassium permanganate is used to disinfect aquariums and utensils that cannot be boiled (tubing, thermometers, etc.).  Fill the aquarium up to the brim with water and put in it all the items to be disinfected.  Then add enough potassium permanganate until the violet color of the water is so intense that you cannot see through the tank anymore.  Let the external filter run without any filter medium so the violet solution rinses all parts of it.  After three days empty the tank and rise it with clean water until all the color is washed away

Method D2

Table salt

Salt can be used for disinfection.  Dissolve 350 g salt in 1 liter of water.  Disinfection of an aquarium in this way would be expensive and inconvenient, but the method is ideal to sterilize nets and other small utensils.

Prepare a bucket containing a salt solution at this concentration and leave the nets standing in it.  A net should be in it 24 hours before being reused.  Since the salt solution never goes bad or gets weaker, a bucketful lasts a long time.  Use tap water to replace water from the bucket as it evaporates.  If you color it slightly with a little methylene blue, it will not be confused with other buckets of solutions.

Empty aquariums can be scrubbed out with a slurry of salt and salt solution.  Let the slurry dry on the glass panes of the tank and repeat the whole operation another five times over the next few days.

Method D3

Hydrogen peroxide (30%)

Caution:  Hydrogen peroxide at 30% concentration is highly corrosive.  Do not let this product come into contact with skin or clothing.

Hydrogen peroxide can be decomposed into oxygen and ordinary water by light, thus it is stored in brown or amber bottles.  To disinfect an empty aquarium, add 50 ml of 3-% hydrogen peroxide to 100 liters of water.  Landscaping articles and utensils can go into the solution.  Gravel is best disinfected by baking it at 150 degrees C for two hours (not counting warm-up time), otherwise the hydrogen peroxide will be exhausted too quickly.  Let the filter operate, but without any contents (see D1).  Let the solution stand in the tank for three days, with the lamp turned on during this time.  Then empty the tank and rise it out with tap water.  The advantage of this method is that it does not leave any residual matter that would have to be meticulously cleaned out later.

Method D4


Disinfection of plants is the major use of alum in aquariums.  At pet shops, water plants that are not kept in separate plant tanks but in tanks along with fish could transmit pathogens and their various resting stages to your aquarium at home.  Because these plants do not do well in quarantine tanks, you have to disinfect them before replanting them in the aquarium.  Dissolve a heaped teaspoon of alum in a liter of water and soak the plants in it for five minutes.  Then rinse them off thoroughly with fresh water before planting in the aquarium.

Method D5

Isopropanol, ispropyl alcohol

Many aquarists my feel the need to disinfect their hands in addition to washing them after autopsy of a fish.  That is, as a rule, not necessary since fish diseases generally are not transmitted to man.  Tuberculosis, however, is an exception.

Commercially available 100% iso propanol is diluted to 70% (US drugstores often carry several strengths, one of which is 70%).  To dilute, measure off 70 ml of the 100% isopropanol in a graduated cylinder, then simply add enough water to bring it up to the 100 ml mark.  Then, after washing them with soap and water, wet your hands with this alcohol and let them dry in the air.  This 70% working solution  is also good for soaking small utensils and tubing to disinfect them.

If you fill a spray bottle (such as used for spraying a water mist on plants) with 70% isprpanol, you can disinfect empty tanks and other large objects with it.  Spray all surfaces, particularly the hard-to-reach-inside corners, thoroughly and evenly, then let them dry.  Repeat the spraying in a few hours.  The alcohol evaporates without leaving any residue, so the aquarium can be filled up again after the alcohol dries.

Method D6 


Add 30 ml of the normally available 35-40% formalin to a 10-liter bucket (that can be closed with a cover) and fill with water to capacity.  To avoid confusion, color the solution with methylene blue.  Nets and other small objects can be dipped into this solution.  A two-hour bath disinfects with absolute certainty

This method is not without its risks in an enclosed area, since formalin (actually formaldehyde) fumes in the air can irritate the respiratory passages.  Working with formalin solutions can irritate the skin.  In addition, remember that formalin is carcinogenic.

*Information by the Handbook of Fish Diseases, Copyright 1989, Dieter Untergasser--edited for the English language by Dr. Hebert R. Axelrod.  Published by TFH publications.


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