AQUARIUM & POND ANSWERS;
Freshwater, Marine, Sick Fish, Lighting, Baths

 

Fish Baths/Dips for supplemental (& even primary) treatment of Bacterial infections, wounds, sores, Fungus (Saprolegnia), parasite infestations & more

By Carl Strohmeyer-PAMR 40+ years experience

Sections:
Basic Ingredients What is a Bath or Dip used For What is Better; A Bath or Dip Performing a Fish Bath Important Bath Tips Bath Risks Medications in Baths Alternatives to Methylene Blue	Potassium Permanganate Cautions Dips, Swabs, etc. Coral, Anemone Dip Helpful Conversions (metric to SAE, etc.) Bath Video Feedback Article/e-book Download

Updated 11/26/24

Although the Article; "Aquarium Disease Prevention" has a relatively in depth explanation of how to perform (& why) a fish bath or dip, this Aquarium Answers post/article will hopefully expand more on this subject for a better understanding. I am also including input from members of Everything Aquatic Forum to further assist in this article.

References:
*Principles of Aquarium disease Prevention and Treatment
*Everything Aquatic; Aquarium Forum Board
*Everything Aquatic; Performing a Medicated Fish Bath

The use of Swabs and Dips is also discussed in this article.

Why a Fish Bath (both positives and negatives)?

• Provides an environment to use products that might otherwise harm your display aquarium, in particular the nitrogen cycle.
  While Methylene Blue can be used in the main aquarium, it is generally more effective in concentrations best served in a bath without the risk to the bio filter.


• Allow for stronger short term exposure to medications, which can be important for some more delicate fish


• Allow for use of osmoregulators such as sodium chlorides or magnesium sulfate (Epsom Salt) in dosages that may not necessarily be therapeutic but definitely allow for the pulling of fluids through the body of the fish which can help with cleansing of toxins and help with treatment of Swim Bladder issues, Dropsy, or similar.
  These concentrations that are more effective of sodium chloride/magnesium sulfate generally are not safe for use in the main aquarium for long term exposure.
  
  As for magnesium sulfate (Epsom salt), while I have not specifically know the mechanism, what I do know from experimenting around is that it works well in a bath, but is actually detrimental “in-tank” for freshwater.
  My guess is magnesium is more of a controlling osmoregulator like sodium chloride can be as well, not something the fish need much of.
  As an analogy, think of how our atmosphere is mostly nitrogen, yet it is oxygen that we utilize. Ditto magnesium sulfate in water, especially marine aquariums, but over loading in freshwater long term seems to have a negative affect, while a short term bath of magnesium sulfate seems to help draw fluids though the fish in a therapeutic way


• For genetically weak or old fish, a bath can provide for a treatment while not affecting the main aquarium environment, which most medications used in tank have a negative affect on the aquarium environment.
  As well the fish bath often makes a good compliment to in tank treatments, especially when using a more mild treatment such as AAP/API Pimafix.


• A negative for a fish bath, especially for large fish is the potential stress & injury of netting and moving a fish back & forth.
  For me this was not too much of a problem, but if you are nervous, this can become more of an issue.
  
  A way to mitigate this is by having a small breeder box as later discussed in this article.
  Another way for larger fish is to house your large fish in a separate large hospital tank that becomes their bath for 30 minutes once or twice per day, then is flushed with water from the display tank after the bath, while the display tank gets fresh water.

The basic ingredients of a bath include:

• Salt (Sodium Chloride)
  Further Reference: Salt Use in Freshwater Aquariums
• Methylene Blue (standard 2.303% solution or premium AAP MethyBlu 5% solution).
Methylene Blue can be substituted with Potassium Permanganate (standard 3.84% solution) in certain instances
• Epson Salts (Magnesium sulfate) in small amounts can be used as well for added aid in internal issues
• Further medications can be added (this will be addressed later in this article)

What is a Bath or Dip used for in the Treatment of Fish Diseases or Similar?

• Treatment of sores or injuries, especially open sores that expose deeper tissues (often minor injuries do not require a bath/dip).
  The Methylene Blue will stain tissues and aid in prevention of bacterial growth (it is normal to stain areas of the fish that has lost their natural slime coat), as well Methylene Blue will increase available oxygen to tissues. Swabbing (or dripping) the wound, sore, or red streaks (caused by Septicemia) with Methylene Blue prior to a bath often increases the effectiveness.
  
  Recommended Product Sources:
  *AAP MethyBlu Premium Concentrated Methylene Blue (recommended)
  *Standard Methylene Blue from AAP


• As an Aid to Ich, Velvet and similar parasite infections.
  Although a bath or dip is not an effective cure for in tank Ich infestations or similar, a bath/dip can increase survivability in severe cases as the bath/dip provides critically needed oxygen to gills/tissues (via the Methylene Blue), as well Methylene Blue will often stain the parasite on the fish and weaken it severely (keep in mind that Methylene Blue was used as an early Malaria treatment, and that Malaria is a protozoan as is Ich and Velvet).
  The use of baths/dips with sensitive fish such as Clown Loaches is often a must in my experience for moderate to severe Ich (Ichthyophthirius) infestations.
  
  Further References:
  *Treatment and identification of Freshwater and Marine Ich, White Spot Disease
  *Treatment and Identification of Freshwater Velvet, Costia


• As an aid to bacterial infections (such as Columnaris) or Saprolegnia (Fungus).
  As with wounds/sores, swabbing or dripping the Methylene Blue directly on areas of infection greatly increases effectiveness.
  
  Further References:
  *Treatment and Identification Columnaris, Saddleback, Cotton Wool Disease
  *Treatment, Lifecycle, and Identification of Saprolegnia/Fungus in Fish


• As an aid to and for treatment of osmoregulation problems in fish such as Bloating and even Dropsy.
  
  Further References:
  *Do Fish Drink, Healthy Fish Osmotic Function
  *Prevention and possible treatment of Dropsy in Fish


• As an aid to ammonia/nitrite poisoning, often as the result of poor handling/shipping and over crowded conditions prior to an aquarist obtaining a new fish.
  The Methylene Blue will be absorbed into the blood, kidneys, and liver where is can help lessen the effect of ammonia and nitrite poisoning.
  
  Further Reference: Aquarium Medications Part 3; Methylene Blue & How it Works

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What is Better; a Bath or Dip?

This is a subjective question that can not be simply answered however I will give some generalizations.
A properly performed bath is much less stressful to the fish than most disease that they are being treated for. The most stressful part is capture of the fish which can be minimized with a breeder/holding net or proper netting.
In fact I have seen fish bounce back from baths within a hour, especially when the use of stress reducing and medicated water conditioner is used directly on the fish and in the water as the fish is returned to the aquarium. The best product for this by far is the professional water conditioner AAP Res-Q.

Resource: AAP Res-Cue/Res-Q

So with this in mind a mild to moderate infection or for many quarantine purposes the bath is the better choice.
As well almost any injury is better treated with a bath since stress is a major factor with an injury.
I often use baths over in tank treatments where “tank wide infections” are not present so as to not interfere with the biology of the aquatic environment in any way.

A dip is often a choice of last resort for seriously ill fish, especially with Dropsy, bladder infections or other infections causing osmoregulation problems.
One exception for healthy fish where I often choose a dip over a bath is for the prevention of Ich, Cryptocaryon, Oodinium and similar parasite infections.
I have not seen a healthy fish ever succumb from a dip when used for this purpose and a dip is nearly 100% effective for such prevention in marine fish, however less effective and more harsh for freshwater fish (provided there is not latent infection already in the aquarium).

A dip is NOT a good choice for seriously injured fish or fish that have considerable open tissue due to infection, as the dip will often make this worse by extracting necessary body fluids that are already being lost. For these fish, the bath is the vastly better choice.

Performing a Fish Bath

(expanded from Aquarium Disease Prevention);

A bath can be performed in as little as 1 quart of water, in a 1 gallon Rubbermaid (or similar) container or a small BARE tank. Generally the larger the better since it is easier to maintain dissolved oxygen levels and figure out the amounts of medication (if used) in larger containers
If I use a 1 quart container, I would use 1/4 teaspoon of salt and several drops of MB (I also recommend rubber gloves and old towels, rags, paper, etc spread around since Methylene Blue is messy and stains).

The schedule is generally 20-30 minutes at least once per day, twice if the fish will tolerate this frequency.

For freshwater I would add Methylene Blue at double normal tank treatment strength (as per bottle instructions) then add salt (NaCl) at about 1 teaspoon per gallon. With the Premium AAP 5% solution "MethyBlu" (recommended), this means 2 drops per gallon
Epsom Salts can also be used too at 1/4 teaspoon per gallon in baths used for treatment (some use higher amounts, but I find this works well when combined with sodium chlorides salt). Epsom Salt is especially useful in cases of bloat, water retention, swim bladder issues, etc. This salt should be pre-dissolved prior to introduction of fish to prevent burning of gills.

The salt (regular salt; NaCl) can be increased for difficult treatments (such as Columnaris), especially with salt tolerant fish such as livebearers. Sodium Chloride (NaCl salt) is not only helpful for many external bacterial issues, it also acts to pull fluids through the fish' body often helping with internal osmorgulation issues.
It is best to slowly add dissolved salt to increase levels gently in salt amounts over 3 teaspoons per gallon, even in salt tolerant fish.
Generally for most fish (even catfish based on University of Florida studies) 2 teaspoons per gallon can be tolerated for up to 30 minutes (many fish can tolerate 4 teaspoons per gallon), although if unsure about your fish’ tolerance, gradually add the salt via a dissolved solution during the first half of the bath.

Epsom salts (Magnesium Sulfate) are useful for baths (I do not recommend even short term use in the main display aquarium) in either fresh or saltwater where internal issues are suspected, including constipation and lack of appetite.
This said, Epsom salts are generally not enough alone except for very specific internal bloating issues and other more specific medications will need to be added to the bath (read further in this article, including references/resources).

IMPORTANT TIPS; Please Read Before Performing a Fish Bath:

• I recommend keeping the “bath” container in a location that does not allow the temperature to drop more than 2 degrees during this time so as to prevent shock when transferred back to the holding/display tank.


• If at all possible I recommend keeping the fish that are being given baths in a Breeder Net Box (see picture) or similar in the tank or in another filtered bare tank so as to make capture easy and less stressful for both you and the fish.
  If too much stress is incurred capturing the fish for each bath, this can negate the positive effects of the bath.
  Product Source: Lees Breeder Net/Box for Sick Fish, Bath Holding


• Netting the fish can be stressful to both the fish keeper and the fish, so the above suggested holding tank container can help here.
  If possible, simply cupping your hands or using a ladle will lower risks of fin damage and loss of slime coat via net capture.
  
  That said, remaining calm yourself goes a long ways in preventing stress & injury to the fish to be given a bath, dip or swab. Often injuries only occur to the fish because the fish keeper is nervous and this results in rough handling. I personally have netted many fish over the years for baths, dips or swabs with no injury whatsoever.


• ALL baths should start with water from the fish’ holding tank's water, so as to avoid pH and temperature shock.
  As well, ALL baths should have fresh Methylene Blue, salt & other medications if used, otherwise many medications can and will degrade and be less effective or even toxic in some cases.
  The bottom line here is to throw away all bath water after completion of each and every bath, NEVER reuse bath water from a previous bath, even if just used hours earlier!!!
  
  HOWEVER, do not worry if a tiny amount of Methylene Blue or other chemicals/medications is added to the main aquarium when transferring the fish back after the bath.


• Floating pre-made large fish bags of the dip water (with salt, do not add medications until immediate use).
  While this is not essential, this can make the bath process easier as everything is ready to go when you may be in a hurry. As well this allows for the correct water temperature.


• Although most bottles of Methylene Blue do not come with a dropper any more (the premium AAP MethyBlu comes with a dropper style bottle), I recommend finding a dropper that will fit the bottle or use an eye dropper so as to limit MB stains/mess.


• Since mineral cations can help with stress (in part due to improved Redox Balance), I recommend to use a product such as the Wonder Shells in the bath water (also dip water too).
  You can break off a piece of Wonder Shell for this bath, then leaving this piece in the bath for the duration of the bath to add these mineral ions.
  Product Source: AAP Wonder Shell; Fresh, NOT clearance (BEWARE of Copycats from Amazon and Aquarium Co-op, INSIST on the genuine fresh Wonder shells only at AAP)


• Be careful of too many or too large a fish in too small a volume of water, as dissolved oxygen can be quickly depleted. A fish "starving" for oxygen defeats any benefits a bath might provide.
  Consider an air stone in the bath water to address this potential issue.


• I generally do not recommend baths for larger fish (unless you are sure of your fish handling abilities), such as over 6-8 inches (15- 20 cm.), as often handling of these fish can be difficult and cause quite a mess.
  As well larger fish can be more easily injured due to the difficulty in handling them.
  However, if a larger fish is in poor condition and question arises that the fish is already in a severely weakened condition, a bath or better, a dip may be attempted (see below for more about “dips”).
  As noted earlier in this article, a way around this is to house your large fish in a separate large hospital tank that becomes their bath for 30 minutes once or twice per day, then is flushed with water from the display tank after the bath, while the display tank gets fresh water.


• For saltwater fish, dilute the saltwater to 1.015 or even 1.009 (specific gravity), making sure your pH stays up by adding any buffers necessary before adding fish (1.009 is a must for Cryptocaryon prevention/removal).
  The purpose of adding or lowering salt (whether SW or FW) is to change osmotic pressure which is an aid to parasite removal as most parasites such as Ich or Cryptocaryon cannot tolerate these changes as well as fish.


• With freshwater fish, AAP/SeaChem StressGuard or AAP Res-Q are good follow ups to a bath, dip or swab.
  The professional choice, AAP Res-Q, is preferable over Stress Coat as it tend to be more attracted to the fish epidermis when squirted directly on the fish when releasing back into the aquarium and adds Sulfa & quinine hydrochloride to aid in healing.
  
  Product Resource: AAP Res-Cue/Res Q


• Finally, Do not add bath water back to your aquarium (a small inadvertent amount when adding back fish is not going to to create issues with your aquarium water).
  However continued addition of all Methylene Blue & other chemicals, salt, medications, etc. can destroy your nitrifying bio filter bed or cause other water quality issues.

Please see the video at the end of this article for more help in understanding the process of a fish bath

Further Bath Tips from Everything Aquatic Member Fishfever

1. Always spread out an absorbent mat around the tank before doing anything to catch drips (and especially Methylene Blue, ***IT REALLY STAINS IF IT GETS ON ANYTHING ***). Gloves are good too to avoid the blue finger syndrome!


2. Premixing the salt with tank water in a large container saves time if you plan to give a number of baths. You could probably premix the MB also (not sure) but would not mix Potassium Permanganate since it reacts with tank water (I think it removes dissolved organic compounds in the tank water).
   I use an eyedropper to get the proper fraction of a teaspoon to gallon ratio for the Potassium Permanganate in the small bath container or double bag (it's not a perfect ratio but it's consistent).
   Product Source: Potassium Permanganate from AAP
   
   Further Information: Aquarium Medications 3; Potassium Permanganate


3. If possible, give your bath in a container or double bags within the tank.
   This way the bath stays heated to the same temperature as the tank and if the fish jump they just jump into the tank. I fill my bath container or double bags just enough so they still float and the buoyancy pushes the container up against the rim and top cover, keeping it from trying to flip over.
   If you overfill the bath container will sink. Remember to float the bath container or bags in your tank long enough to equalize temperatures.


4. Since I have to give twice daily baths, I leave the fish in a small breeder net (about 6"x6"x4") overnight after the evening bath which I do just before I shut the tank light out and go to bed. This saves me from having to catch the fish for the morning bath, i.e. only have to catch her once a day for the evening bath.

Bath/Dip Risks

Obviously there are risks in the performance of a fish bath or dip, however in fish less than 6 inches these can often be minimized as per previously suggested tips.
For minor injuries or infections sometimes the risk of stress is simply not worth the bath, HOWEVER in my experience with literally 100s (if not 1000s) of baths/dips the risks for most applications is far less than the alternative.
Even with 'extreme' freshwater dips used for saltwater fish, whereby the fish will react as if they are dead, the fish will generally “snap out of it” in a matter of hours and will be better than before this dip.
Most baths are much less stressful than the previous example, so any observed stress will pass quickly if the bath is performed correctly.

As well in many cases such as sores or diseases, the use of a bath will allow for a more mild in tank treatment which is quite bluntly better for long term aquarium health than dumping in “tons” of harsh medications (especially when a hospital/treatment tank is not available).
The bottom line is to not let the bath/dip stress you more than the fish, as this procedure can often mean the difference of a successful treatment and an unsuccessful treatment especially in severe cases of Ich (this is especially true with sensitive fish such as Loaches) or in often difficult to treat bacterial infections such as Columnaris.

Further References:
*Aquarium Ich in Freshwater or Saltwater
*Columnaris & Fungus in Aquariums

Medications in Baths;

Another option to baths is IN ADDITION to the salts and Methylene Blue, but NOT combined with Potassium Permanganate, is you can safely add many antibiotics at double normal "in tank" recommended dose for the 30 minute bath. This can both increase the effectiveness of the bath and the antibiotic added.

Before I go on here, it is noteworthy that with any aquarium/pond fish treatment it is important to know all the steps as often treatment is much more than a medicated fish bath or dumping medication into an aquarium.
Please read this article before ANY aquarium treatment regimen:
Fish Diseases | How to Treat Sick Fish

Medications that generally are good choices for baths are;

• AAP Nitrofuracin Green; Synergistic Nitrofurazone, Sulfathiazole Sodium, & Methylene Blue Full Spectrum Treatment
  Probably the FIRST CHOICE for a fish baths since this blend is wide spectrum bacterial, fungal, and even anti-parasitic. As well this product already includes Methylene Blue so this negates the use of Methylene Blue in your fish bath wif this medication is used. Use this at double aquarium/tank dose.
• Metronidazole
  A good choice for intestinal infections since it is not readily absorbed through the intestines.
• AAP "Yellow Powder"; Premium Nitrofurazone
  For Aeromonas, Saprolegnia, Furunculosis, & serious cases of Columnaris.
• AAP Kanaplex (Kanamycin)
  OR Minocyline for Columnaris (mild cases when used by itself), Dropsy, or PART of a treatment for Pop-Eye.
• AAP Sulfaplex; Sulfathiazole; a good option (not combined with other antibiotics/anti-microbials) when there wounds, abrasions, etc. as the root cause of an external infection. While generally not the first choice for Pop-eye, it can be if a wound or similar is the cause.
  
  Further Information: Aquarium Medications Part 2; Sulfathiazole


• Malachite Green can also be added to Methylene Blue to increase effectiveness for fungal infections as well as parasites.
  Recommended Resource: AAP Seachem Paraguard (Zinc Free MG)
• AAP Pipzine is a good choice for: Unexplained Fish Death, Gourami Disease, & Gasping & Surface Breathing.
• While primarily meant as a fish food soak, AAP Discomed is still a good choice for Color Loss, Weight Loss and Wasting, Darkened Body Color, Skinny Body, & Concaved Abdomen; ALL as a result of parasitic infections.
  This product also already contains NaCl, Piperazine & Magnesium Sulfate, so these salts need not be added to the fish bath.
• Usnea is an experimental alternative that has similar properties to Metronidazole and can also be effective for some viruses and possibly tumors. I use about 1 tablespoon per 6 oz. preparation for a 1 quart bath.
  Please see this article for more about the use of Usnea:
  Usnea as a Fish Disease Remedy

Alternatives to Methylene Blue

Acriflavin, at double recommended tank dose can be substituted for Methylene Blue for treatment baths for ailments such as wounds, and very stubborn fungus infections (which can be common in bettas kept in confined spaces).
Product Source: API Yellow Powder, Nitrofurazone & Acriflavin

Kordon Fish Therapy Curative Bath, This is an all natural fish bath developed by Kordon containing natural therapeutic oils (including citrus, neem, and lavender oils), and aloe vera.
However do not be fooled thinking that just because it is natural, it is therefore better, as this is NOT a replacement of Methylene Blue for fish suffering from ammonia poisoning, low oxygen damage, pH shock, or other bath medications for more serious problems.

This product is best used without any other medications as an alternative treatment or preventative for suspected mild to some moderate problems, in particular if parasites are suspected (either internal or external). Use with salts is OK and suggested for moderate to serious issues (either or both Epsom Salt or Sodium Chloride).

Potassium Permanganate (at double recommended tank dose) can be substituted for Methylene Blue for treatment baths for ailments such as Flukes, cloudy eyes, & some stubborn parasite and bacterial infections such as Columnaris(generally Potassium Permanganate is the better choice for Columnaris unless the fish is displaying rapid breathing or is on "death's door").
Product Source: AAP/Jungle Potassium Permanganate, Clear Water

HOWEVER for "pure" preventative baths, ammonia poisoning or unknown problems, Methylene Blue is by far the better choice.

Unlike Methylene Blue; DO NOT mix Potassium Permanganate with antibiotics.

See this article under Potassium Permanganate or Methylene Blue for more:
Aquarium Medications; Chemical Treatments.

Another key point is that Methylene Blue can quite SAFELY be overdosed as it takes high amounts with long term exposure to be toxic, while Potassium Permanganate should NEVER be overdosed.

CAUTIONS About the Use of Potassium Permanganate for Baths & Painting (Swabbing) Infections:

Since Potassium Permanganate is strong oxidizer, caution should be exercised in usage for baths and especially as direct application for external infections (unlike Methylene Blue which is very difficult to over dose).
For most fish, a double dose of the normal 'in tank' recommended dosage is used.
This varies from product to product, however using Jungle Clear Water as an example; the recommended tank dosage is 5 mL per ten gallons, so the bath dosage would be 10 mL per ten gallons (or 5 mL per 5 gallons of “bath” water).
Fish such as many Tetras, Loaches, and similar “sensitive” fish should be given consideration in dosage of Potassium Permanganate.

An even more important consideration is the use of Potassium Permanganate for direct application/swabbing of certain infections such as external symptoms of Columnaris or Saprolegnia/Fungus (see the next section for more about swabbing/dips).

Potassium Permanganate should be diluted at least 3/1 up to 2/1 (water/PP) for this use and often more so depending upon the fish in question (testing on a healthy part of the fish in question or a related fish may help determine tolerance).
As well do NOT use even diluted PP anywhere near the gills of a fish, or on fish tissue showing signs of necrosis [1], THIS CAN BE LETHAL.
Use a diluted PP swab ONLY on areas of actual Columnaris, Saprolegnia, or related infection such as the common "Saddleback" often seen in Columnaris or the fuzzy growth areas of Saprolegnia.

If Potassium Permanganate or Hydrogen Peroxide is accidentally applied directly to the gills, an immediate 3-5 minute dip in water with a 2-3 x normal dose of SeaChem Prime or other similar water conditioner is a must!
The use of AAP Res-Q or Prime or other similar water conditioner at double strength in a 2-5 minute dip (using tank water) is also strongly suggest after a bath using Potassium Permanganate or Hydrogen Peroxide if only to help restore the slime coat and restore the fish Redox Balance since most aquarium water conditioners are temporary Redox Reducers.

Product Sources:
SeaChem Prime, Temporary Redox Reducer AAP Res-Q; Premium Medicated Bandage, Reducer, & Slime Coat Protector

Further Information: Aquarium Water Conditioner Review

Please note that this point of dilution does NOT apply to Methylene Blue which is safe to use full strength, even around gills (although internal gill application is best performed via a bath, not a swab).

Dips, Swabbing (Swabs), etc.

In a dip, I again adjust pH and add Methylene Blue, HOWEVER in the case of the marine fish, I will use a specific gravity of 1.001 (basically a freshwater dip) and a specific gravity of 1.012 of 1.015 for the freshwater fish (2.3 oz. or approximately ¼ cup of fine salt per gallon) which is basically a saltwater dip.
This dip should be no less than 3 minutes and no more than 5 minutes to be effective.

For known problems (or sometimes as a preventative for new fish especially as a Cryptocaryon or Oodinium in marine fish) a 3-5 minute dip is sometimes even more effective, albeit more stressful to the fish (more stressful for freshwater fish than saltwater fish).
The picture to the right displays an Ocellaris Clownfish in freshwater dip for Oodinium treatment.

To lower the stress a high salt dip for freshwater fish or a freshwater dip for marine fish it is advisable to use the first 2 minutes (of a 5 minute dip) slowly introducing the saltwater (or freshwater for marine fish) until the fish is in the desired salinity water for the remaining 3 minutes.
Make sure that the water added slowly during the first 2 minutes is pre-mixed with salt prior to use for freshwater fish or pre-adjusted for pH for marine fish.

A dip is often a better choice than a bath for a large or otherwise “spastic” fish due to the much shorter duration.
As well a dip, albeit much more harsh than a bath (when used as described), may be a better choice for a very ill fish that may be “at deaths door” and the risks of a dip are low when compared to the fact of the probable imminent death of the fish anyway.
A dip is also a good choice for problems that stem from fluid build-up and poor osmotic function, such as many causes of “Pop-Eye”.

*I also use dips to replace quarantine when quarantine is not possible for fish of questionable sources; especially with marine fish as a dip is nearly 100% effective for destroying Oodinium or Cryptocaryon on marine fish (the osmotic pressure causes the parasite cells to burst). Keep in mind that the dip does not destroy these parasites in the water column if the disease has already been accidentally introduced.

Further Reading:
*Oodinium in Marine Fish
*Marine Ich, Cryptocaryon

*SWABS:

Another similar idea is to directly drop or “paint” with a Q-Tip (or similar implement) Methylene Blue, Mebromin (AAP Wound Control), Potassium Permanganate (diluted), tincture of Iodine, or Hydrogen Peroxide onto a problem area such as Saprolegnia/fungus, Columnaris, Ichthyophonus, or similar.
This can be VERY effective for stubborn external infected areas on a fish (such as node on fish tails, etc.) as well as a first response to a wound or injury.

The negative of swabs is these can be even much more difficult to perform for a nervous fish keeper than a bath, so staying calm is very important. As well, while remaining calm, it is best to firmly but gently handle the fish so as to prevent injury. I prefer using my hands once captured, not a net.
For larger specimens I will use a smooth container with square sides to more easily hold the fish firmly.

Methylene Blue is safe to use for exposed tissue, which will stain blue, but this is not a danger unless grossly over used. However since MB is not very strong, if the area treated still has a slime coat, MB will likely not penetrate well (a swab may not also be called for in such an instance).

The use of Methylene Blue at full strength (in a typical 2.303% solution or concentrated MethyBlu) as a swab, dip, and to a lesser degree a bath will also expose healthy or at least normal tissue as Methylene Blue will generally adhere to infected areas or wounds staining the area “blue” due to the lack of the normal “slime” coating fish have on healthy areas of a fish’ epidermis.
Even scar tissue will generally not stain “blue”, so this a good test of whether or not a “growth/sore” is actually an infection or similar (please note that some cancers/tumors can mimic healthy tissue and not stain blue).

Another alternative to a straight Methylene Blue swab or drops is Mebromin
In fact prior to the demise of availability of this Mebromin around 2002, this was my swab or drop chemical of choice for many applications over Methylene Blue.
While Mebromin does not have the benefits of dying exposed tissue (showing where tissue is compromised) and transport of oxygen to cells, it actually is far more effective for exposed injuries/wounds and severe infections caused by opportunistic bacteria with just as much safety margins as Methylene Blue (unlike Potassium Permanganate and Hydrogen Peroxide) but is vastly more effective for bacteria such as Columnaris and in fact is the swab/direct application of choice in such bacterium.

For really serious exposed infections, such as flesh eating bacteria (which is difficult to treat), is a combination where the aquarium fish keeper first uses AAP Wound Control to stop & kill the infection, followed by placing the sick fish in a holding container for 5-10 minutes then follow with a MethyBlu swab which although not as effective on bacterium, it is better at promoting healing and getting oxygen to sick tissue.

Product Resource: AAP Mebromin (Wound Control)

For serious infections such as advanced cases of Columnaris/Sadddleback Disease, a swab with Merbromin (AAP Wound Control) or Potassium Permanganate (as discussed earlier in the article in detail) should be performed, then possibly follow a couple hours later with AAP/SeaChem StressGuard.
As already noted, some sores, blisters, tumors, etc., may not allow adhesion of Methylene Blue/MethyBlu and AAP Res-Q may not be enough, this is where the use of Merbromin or maybe Potassium Permanganate may be called for.
Please Review "Potassium Permanganate Cautions" before using.

If Potassium Permanganate or Hydrogen Peroxide is used as a swab; placing the fish into a quick dip utilizing a double dose of any Redox Reducing Water Conditioner such as SeaChem Prime,AAP Res-Q, or AAP Sheildex can immediately stop any unwanted oxidation of Potassium Permanganate on the fish.

Product Sources:
Prime Aquarium Water Conditioner from AAP
Potassium Permanganate; Clear Water from AAP

Further Information about Redox: Aquarium Redox

After swabbing, the use of AAP/SeaChem StressGuard in the aquarium is suggested.

Product Resource:
StressGuard from AAP

For stubborn Fin rot or infections direct application of 3% Hydrogen Peroxide via swab has been successful on many occasions.
Further Information: Aquarium Medications 3; Hydrogen Peroxide

Potassium Permanganate (this should be diluted approximately 50% to 60%, unlike Methylene Blue) & Hydrogen Peroxide are generally more effective for the above noted infections.
However open sores, wounds, and in particular gill problems should Not use Potassium Permanganate.

Hydrogen Peroxide or tincture of Iodine may be used (EXCEPT for gills), however Methylene Blue is a better choice direct gill applications where PP or Hydrogen Peroxide will burn the gills and often kill the fish as a consequence.

If Tincture of Iodine is used as a swab, a quick dip into some "throw away" water after the swab can help prevent toxic levels of iodine in the aquarium due to excess iodine on the fish after the swab.

Any of these swabs can also be used in conjunction with baths and "in tank" treatments too.

Finally, for stubborn fungal infections, Acriflavin (found in API Fungus Cure) is another good swab choice, especially for Bettas normally kept in small tanks/bowls.

CORAL, ANEMONE DIP OR BATH

Often a dip of anemones or coral (such as Acropora corals) is necessary to remove bacterial, parasites, planarian, etc.
Further Reference: Fish Parasites, Flatworms, more

A simple freshwater dip using de-clorinated freshwater adjusted to the pH of the water of the saltwater containing the specimen to be dipped is often "good enough" for many problems.
This should be between 3-5 minutes to be effective for "bugs" such as Oodinium.

Iodine Baths are excellent for some potential parasites of corals such as flatworms.
For a home method, the use of Tincture of Iodine 2.5% can work well and is available over the counter at most drug stores.
Use 1 Liter (approximately 1 quart) of Tank water, then added 20 drops of Tincture of Iodine 2.5%. Then fill a second container with tank water only, this is for rinsing dipped (bathed) corals.

Place your corals including both SPS and LPS in this bath for approximately 20 minutes (do NOT exceed 25 minutes).
This is followed by rinsing the corals gently in the rinsing the corals for about 30 seconds with a swirling motion.

An excellent and SAFE product to use is SeaChem Reef Dip, which contains elemental iodine complexed to a protective slime coat for safely and gently disinfecting corals.
SeaChem Reef Dip can be used prophylactically or to remedy diseased specimens. It is safe to use with both stony and soft corals. It is also safe for anemones and polyps.
Product Source: Reef Dip; Contains Elemental Iodine Complexed to a Protective Slime Coat

A FEW HELPFUL CONVERSIONS

(Use accurate teaspoons, not silverware):

• Teaspoon = 4.929 mL
• Tablespoon = .5 fl. oz. = 14.787 mL
• For mixing salt for a dip; 1/2 dry cup will make a specific gravity of about 1.023- 1.025;
  For 1.015 specific gravity for a dip, use approximately 1/4 to 1/3 dry cup.

Fish Bath Video;

Feedback

Carl,

Just like to thank you for the information. Our fish is doing GREAT! I wish I had a before and after picture. He had turned completely black lost so much weight and his tail was almost completely gone. I really didn’t think there was much of a chance that he’d make it. I did the fish baths with Aquarium salt, Methyl Blue, Kanaplex, and Metronidazole for 10 days. Now he has gained weight and has almost caught back up w/ our other fish. He has turned back completely to gold except his fins which were black to start with. Its truly amazing. My girls would have been heartbroken if he had not made it.

Thanks again.
Jennifer Arnder

Glossary of Terms

*[1] Necrosis: Localized tissue death that occurs in groups of cells in response to disease or injury. This often results in large growing sores and exposed deep tissues of the fish.

Related Tips:

If you use a UV Sterilizer for Fish disease prevention and improved Redox (for fish immunity improvement), it is important to change the UV Bulb every six months for maximum effectiveness!

Product Sources:
*Aquarium, Pond UV Sterilizers
*Premium Low Pressure UV-C Replacement Bulbs/Lamps, Page One

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Labels: fish bath, fish dip, fish quarantine, fish swab, methylene blue treatment, sick fish