Aquarium Medications

By: Carl Strohmeyer

This article (which will continue to grow with information) is informational about different aquarium (and pond) treatments. I give the gram negative or gram positive applications where they apply.

When you have fish that are sick (bacterial, fungal, protozoan, or other parasites), you want to try and isolate them in a hospital aquarium whenever possible. Regular water changes before each treatment allow for a more effective treatment, especially when treated in the display aquarium.

Sponge Filters work well in hospital aquariums. Remember to remove carbon, as carbon will remove many medications. Also note that silicone in the aquarium will absorb malachite green , methylene blue, and copper sulfate. Most corals (crushed and otherwise), and ceramic decorations will also absorb medications such as malachite green, methylene blue, and copper sulfate.

Proper calcium levels are important, as calcium also helps in healing and stress, and without proper calcium levels healing may be diffficult or impossible. The addition of antibiotics (such as Tetracycline) will lower calcium absorbtion.

For more infomation about calcium, see this article: CALCIUM, MAGNESIUM, AND KH IN AQUARIUMS

"Medicated Wonder Shells" deliver medication for ich and fungus treatment and control kH (Calcium) levels.

TRIPLE SULFA (Sulfamerazine, Sulfamethazine, Sulfathiazole):

Sulfas are all antibacterials. These drugs produce are bacteriostatic, meaning they inhibit the growth of the bacteria but do not kill them.

Sulfa drugs arrest cell growth by inhibiting the synthesis of folic acid, a component required for growth by bacteria. Folic acid is a large molecule and is unable to enter bacterial cells, so the bacteria must synthesize the compound intracellularly. Animal cells are unable to synthesize folic acid and it must be provided in the diet. For this reason sulfa drugs are not toxic to animal cells.

USE: A broad spectrum antibacterial medication, fin and tail rot, mouth fungus and collapsed fins, columnaris, and hemorrhagic septicemia. Also useful for damaged fins caused by fin nipping. An old standby that is still usefull and can be used in combination with Malachite Green or Acriflavin (do not combine with copper sulfate). Sulfas are more effective at higher pH levels.

DOSAGE: 250 mg per 10 gallons every 24 hours with a 25% water change before each treatment. Treat for a minimum of 10 days.


USE: Treatment of bacterial infections mostly gram-positive and some gram-negative infections such as fin and tail rot (split, ragged and deteriorating fin and/or tail), Popeye (protruding eyes, may be cloudy or hazy), gill disease (swollen, discolored gills, gasping for air and a decrease in activity) and secondary infections. It interferes with the production of proteins that the bacteria need to multiply and divide (bacteriostatic). Tetracycline Hydrochloride mode of action is as a protein synthesis inhibitor via an aminoacyl-tRNA binding mechanism to the 30S subunit. Mode of resistance is the loss of cell wall permeability. Note, Teracycline can lower red blood cell count, because of this I would not use with injured fish.

DOSAGE: 250- 500 mg per 20 gallons of water. Every 24 hours with a 25% water change before each treatment. This product will not work in water with a ph above 7.5- NOT FOR MARINE USE!


USE: Resistant strains of Ich (especially on scale less fish). Protozoan, sliminess of the skin and Rams disease (whirling disease). Also good for resistant strains of Hexamita when combined with Metronidazole.

DOSAGE : 250 mg per 10 gallons of water. Once a day for 4-5 days. Do a 25% water change before each treatment.


USE: Gram-positive and gram-negative bacteria. Marine ulcer disease, cold water disease, bacterial hemorrhagic septicemia (Symptoms: Red streaks in body and fins, or redness in the body. Open sores or loss of scales) and mouth fungus.

DOSAGE: 250- 500 mg teaspoon per 20 gallons every 24 hours with a 50% water change before each treatment. This antibiotic is best used mixed in with food, especially if your ph is above 8.0..


USE: Bactericidal for some gram-positive and many gram-negative bacteria causing disease in fresh water and marine fishes. This antibacterial is effective for control of flexibacter/columnaris- (Symptoms: Fuzzy, thin, white coating on the body and fins. Looks like a fungus) -works well with Kanamycin for this, Aeromonas (Symptoms: fish have blisters forming on the skin that are full of a clear to yellowish fluid. The blisters may turn into large sores.), Vibrio and related species. Nitrofurazone is particularly useful for control of minor topical skin infections of marine fishes that have not become systemic. Effective against marine ulcer disease and protozoan. Also useful in treating furunculosis found in Koi.

Serious adverse events related to nitrofurans are very rare. Acquired resistance of bacteria to nitrofurans during therapy has been rare and has not appeared on a significant scale in over 50 years of use. Do not use in the presence of invertebrates.

Nitrofurazone is more effective at lower pH levels.

DOSAGE: 250- 500 mg per 20 gallons. Treat every 24 hours with a 50% water change before each treatment. Treat for 10 days.


USE: Gram-negative bacteria (Pseudomonas- Open red sores or ulcerations, fin and tail damage,fins and tail are eaten away, in severe cases, down to the body- treat with Kanamycin for this) and tuberculosis; gram-positive, and possibly mycobacterium. Works well in freshwater or saltwater aquariums.

DOSAGE: 250 mg per 10 gallons of water. Treat every 24 hours with a 25% water change before each treatment. Treat for 10 days. For tuberculosis, use for up to 30 days.


USE: Hole in the head disease (hexamita), chilodonella, plistophora (parasite disease usually seen in neons and cardinals that causes loss of color, darting, and eventually death), salt water ich, bloat.

DOSAGE: 250-500 mg per 20 gallons. Treat every 24 hours with a 25% water change before each treatment. Treat for 10 days.


USE: It is used to treat many sensitive gramnegative and some grampositive bacteria. Works especially well in salt water aquariums. Works well combined with Nitrofurazone for flexibacter (columnaris) (Symptoms: Fuzzy, thin, white coating on the body and fins. Looks like a fungus). Also useful for Pseudomonas-Open red sores or ulcerations, fin and tail damage,fins and tail are eaten away, in severe cases, down to the body. Kanamycin is very effective in high pH applications, especially vibrio, making it useful for brackish and marine treatments.

Kanamycin can be effective for whirling disease , suspected kidney disease and dropsey.

Kanamycin sulfate appears to prevent bacteria from making their cell walls, so the cells die.

DOSAGE: 250-500 mg per 20 gallons. Treat every 48 hours with a 25% water change before each treatment. Treat for 10 days.



USE: Fin and tail rot, infections attributed to kidney disease (often not true kidney infections), pop eye. Most gram-positive and some gram negative bacteria and fungus. Neon Tetra disease (faded color). Black Molly disease.

DOSAGE: 250- 500 mg per 20 gallons every 24 hours with a 25% water change before each treatment. Treat for 10 days.


Dimethyl (2,2,2,Trichloro-1-Hydroxyethyl) Phosphonate:

Trichlorfon is an Organophosphate and degrades rapidly (approximately 99% of applied degraded in 2 hours) in alkaline pond water (pH 8.5) at room temperature. but remains stable in the same pond water held under acidic (pH 5.0) conditions for 2 hours.

Trichlorfon is very highly toxic to invertebrates.

DO NOT USE ON FISH THAT ARE CHEMICALLY SENSITIVE such as: Silver Dollars, Rays, Bala Sharks, Arowanas, Tinfoil Barbs, Hemiodus, Piranha, Most Silver Scaled Fish, Marine sharks, Lion Fish.

See methylene blue if Dylox treatment is not available or viable

USE: Trichlorfon is useful for treatment of: Hydra, Lernia (Anchor Worms), Parasitic Copepods, Monodigenetic and Digenetic Flukes, Fish Lice (Argulus), Leeches

CLOUT contains Trichlorfon (Dimethyl (2,2,2,Trichloro-1-Hydroxyethyl) Phosphonate), as well as; 4-[P-(dimethylamino)-O-phenylbenzylidene]-2, 5-cyclohexadien-1-xylidene dimethylammonium chloride, 1,2,dimethyl-5-nitroimidazole

DOSAGE: There is no recommended dosage (other than Freshwater fish acute toxicity= 1.6-180 ppm), refer to manufacturers directions for all products containing Trichlorfon.


USE: Belonging to the group of beta-lactam antibiotics, ampicillin is able to penetrate Gram-positive and some Gram-negative bacteria.

Even though this a commonly used antibiotic family in humans and other warm blooded animals, this is a family of antibiotics that has shown to be generally useless in fish. About the only effectiveness comes in the treatment of some fungal eye infections. All medications, antimicrobials, antibiotics, chemotherapeutics work differently in differently in different organisms, even if the processes are similar. An example I often use is for Quinine Sulfate; this is a generally safe and effective treatment for fish, but not at all for invertebrates.


USE: Treatment for tuberculosis (Symptoms: the fish have been sick for several months. The fish is lethargic, anorexic, has fin or scale loss and a sunken stomach) in susceptible fish such as Discus. Can be combined with kanamycin.

This is a difficult disease to treat, as treatment can go on for more tha a month.

Also note that this is caused by a very similar bacterium in human TB, but is not the same, and the only danger to humans is to a open wound exposed to the bacterium, which then only causes a localized rash.

DOSAGE: 1 tablet per 20 gallons, every other day for 14- 30 days

METHYLENE BLUE (Zinc Free) 2.303% :

USE: Fungus on eggs, Ich, fungus and some bacteria. Effective in gill disease. Transports oxygen. Some protozoa, sliminess of the skin and oodinium. Great for use as a 30 minute dip at double dose.

Great when used as a dip for topical treatment of parasites, bacterial, and fungal infections. When dylox is not available, this can a useful treatment for anchor worm (especially in goldfish); first carefully remove the anchor worm with tweezers, then dip the affected fish in Methylene blue. When used with a UV sterilizer to kill the swimming stage of the female anchor worm (the female is the parasite), this can be an effective treatment. (Tank can also be treated with Malachite green or malachite green combination during this time for improved effectiveness).

Also useful as a dip for ammonia and nitrite poisoning.

DOSAGE: 1 teaspoon of a 2.303% solution per 10 gallons every other day for 10 days with water changes before each treatment. BEST USED IN A HOSPITAL TANK. Methylene blue can destroy nitrifying bacteria and plants in the display aquarium.


USE: An antiseptic agent for the skin and mucous membranes. It is known to inhibit mitochondriogenesis. Generally used treatment of mild bacterial and fungal infections such as mouth fungus, fin and tail rot, fungus, saproglenia; skin parasites such as oodinium (velvet), sliminess of skin, and ich (although a very mild treatment for ich, FW or SW)

DOSAGE: 1 teaspoon of a 3.84% solution per 10 gallons every other day for 10 days. Combines well with copper sulfate and malachite green.


USE: For treatment and control of various external parasites of freshwater and marine fishes. When used as directed the medication will control or prevent the following common protozoan parasites:

*Ichthyophthinus (freshwater Ich) exhibited as fine "salt like" white spots that usually first appear on the fins.

*Costia (Ichthyobodo). Not to be confused with ich, is a parasite that can live dormant on healthy fish (primarily their gills), then under certain conditions (poor water conditions, stress, ECT), reproduce rapidly. Symptoms of an outbreak include Heavy and labored "breathing" flashing and rubbing, skin cloudiness caused by excess mucus.

*Chilodonella, *Ambiphyra, *Cryptocaryon (marine Ich), *Epistylis, *Oodinium and Trichodina, *Plistophora (best combined with formalin at 1/2 strength)

Malachite Green is also effective against common external fungal infections of fishes and eggs which include Achlya and Saprolegnia.

DOSAGE: 1 teaspoon of a 0.038% solution per 10 gallons every other day for 10-14 days. Or 1 drop of .50% solution per gallon every other day for 10- 14 days. 25% water changes are recommended before each dose. Use half dose for scale-less and delicate fish such as Clown Loaches and Neon Tetras. Double dose for marine aquariums.

Note; malachite green is more toxic at higher ph.

Can be combined with Formalin or Acriflavin.

FORMALIN (3% formaldehyde):

USE: For treatment and control of the diseases caused by fungi, protozoan and monogenetic trematodes of freshwater and marine aquarium fishes. Formalin will control or help prevent diseases of fishes caused by the following disease organisms: *Ichthyophthirius (freshwater "ich"), *Costia (Ichthyobodo), *Chilodonella, *Ambiphyra, *Cryptocaryon (marine "ich"), *Epistylis, *Oodinium, *Amyloodinium, and *Trichodina.

DOSAGE: 1 teaspoon of a 3% solution per 10 gallons every other day for 10 days. Combines well with malachite green.

Formalin can deplete oxygen in an aquarium, so consider adding an airstone or a power head with an air diffuser.


USE: For treatment freshwater and marine ich, Oodinium, external parasites, fungus and even algae. Very effective when used properly and carefully.

DOSAGE: Treat according to your solution to bring your copper level to .15 -.20 ppm. Sequestered Copper (often called chelated, but that is incorrect, chelated means inactivated) sulfate works best (citric acid help achieve this). Soluble copper salts work well in freshwater only. Do use with snails and other invertebrates, do not use in reef aquariums, and note; when uses as an algaecide, the copper is absorbed by the algae then released when it dies. Removal of sequestered copper can be difficult, only EDTA (Ethylene Diamine Tetra Acidic Acid) and water changes remove it, NOT carbon.


There are three organic or "homeopathic" treatments that I have used;


USE: Pimenta extract is effective for a broad range of bacterial and fungal diseases that typically afflict fish and other aquatic animals. Fish diseases that may be treated in accordance with this include bacterial fish diseases, such as fin and tail rot, mouth fungus (often caused by the bacterium Flavobacterium columnaris); fungal fish diseases (such as those caused by microorganisms of the genera Saprolegnia and Achyle) and the like.

Pimafix has also shown effectiveness in the treatment of Dropsey caused by aeromonas or pseudomonas (a disease of the Kidneys that causes bloating and distending of the scales, and is often fatal).

DOSAGE: Refer to Pimafix instructions


USE; Usnea is a lichen of the family Parmeliaceae that grows in damp temperate woodlands.

I have found it effective for bacterial (generally gram negative), fungal and even parasites such ich. This remedy is still in the testing phase, but early results are promising. The Usnea Lichen is proving to be the most effective natural remedy early in my testing

This lichen is boiled like a tea then added to the aquarium.

DOSAGE: None established yet. I boil one small sprig in 6 oz. of water and add this to every 10-20 gallons of water every day until cure is effective +2 days


USE: Repairs damaged fins, ulcers, and open wounds.

Promotes re growth of damaged tissue and fins.

DOSAGE: Refer to Melafix instructions

This is my very basic article, for my Full article that is updated very regularly, please visit this URL: AQUARIUM MEDICATIONS, treatments, how they work, and which ones to use and not to use.


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