Metronidazole; by SeaChem, API, More
Metronidazole is an antibiotic (for anaerobic bacteria) and anti-protozoal medication used to treat various conditions internally and externally in fish.
As for Anaerobic bacteria, these are bacterium that thrive in environments in which there is little oxygen (anaerobic environments) and can cause disease in such environments as the intestinal tract and liver.
Metronidazole belongs to a class of antibiotics known as nitroimidazoles which work by ceasing the growth of bacteria and protozoa. Metronidazole works by selectively blocking some of the functions within the bacterial cells and some parasites resulting in their death.
Metronidazole is metabolized in the liver (whether a fish or a human).
Metronidazoles primary use is for the treatment of ANAEROBIC gram positive & SOME negative bacteria including those that produce beta-lactamase.
However, it is not effective against aerobic bacterium. This means Metronidazole is a poor choice for suspected bacterial diseases in open heavily oxygenated aquariums/ponds such as Columnaris, while it is an excellent choice for diseases of the low/no oxygen environment of the intestinal tract or other internal suspected bacterial pathogens (generally used ina fish food soak for best results).
Metronidazole may be a good choice for any bacterial disease present in low oxygen, high bio-load aquariums or ponds.
As well Metronidazole is effective for some protozoa.
It was originally found effective for the management of infection caused by Trichomonas vaginalis.
For fish applications Metronidazole has been shown to be in particular more effective for internal and external flagellates.
Metronidazole is also sometimes effective for other protozoan parasite infections, especially for Cryptocaryon in marine aquaria as well as Hexamita & Ichthyophthirius.
Metronidazole is often recommended for disease in Cichlids which is often thought to be caused by Hexamita, HOWEVER there is considerable evidence that the cause of "Hole in the Head" is simply the lack of Calcium and even positive calcium ions. This is especially common in aquariums utilizing water softened using sodium chloride or potassium chloride to drive out hard water minerals.
Use of such water should be ceased prior to using Metronidazole and as well, the use of products such as Wonder Shells mineral blocks should also be used first before treating with Metronidazole (or combined).
Hole in the Head Disease
Wonder Shells; Unique Version
Due to Metronidazoles effectiveness against anaerobic bacteria by selectively blocking some of the cell functions of anaerobic bacteria, Metronidazole along with Neomycin is a good choice for bloating of the digestive tract (common in goldfish).
Metronidazole selectively blocks some of the cell functions in anaerobic bacteria, resulting in their demise.
Metronidazole is also effective used in combination (such as with Praziquantel) or by itself for internal parasites such as Nematodes or Trematodes.
In marine aquarium infections is where Metronidazole really shines as it is very effective internally and since Marine fish are always drinking the water around them, medication is easily transported to the infected area.
In Freshwater, treatment can be improved by soaking food as well and this is still an effective freshwater treatment as well.
Directions from SeaChem Metronidazole; use 100 mg. for every 10 gallons (40 L).
Repeat every 2 days until symptoms disappear.
Make sure any UV Sterilizer (if used) is turned off and any carbon, Purigen, Chemipure or similar chemical filter media is also removed during treatment.
To feed (use as for a medicated food), use 100 mg. with approximately i tablespoon of frozen or dried food (fried food would need to be placed in just a enough water to cover and make wet/moist). Feed until symptoms disappear.
Introduction of Metronidazole to the aquarium water when feeding is OK.
Metronidazole can also be used in a fish bath. This is generally performed at double the "in tank" dose as per amount of water used in this bath. I recommend the use of Methylene Blue and maybe salt during this bath treatment too (once or twice per day for 7-10 days).
See: Fish Baths, Dips, Swabs
PRODUCTS CONTAINING METRONIDAZOLE:
*SeaChem Metronidazole, for Purchase
Recommended source to purchase based on extensive aquarium and pond professional experience dating back to 1978.
SeaChem's Metronidazole is the MOST PURE and easily used form of this antibiotic available to the fish keeping community
*Tetra Parasite Guard, for Purchase Contains Praziquantel, Metronidazole, Acriflavin, Diflubenzuron
*API General Cure, for Purchase Contains Metronidazole & Praziquantel
Aquarium Medications 2; Antibiotics, Antimicrobials
*How Medications Work, and Which Ones to Use and Not to Use
Suggested other aquarium information resources & products:
Aquarium UV Sterilization; How UVC Sterilizers Work
Purchasing Aquarium & Pond Equipment via Amazon
Some of the best aquarium treatments available.
Aquarium Heaters; Submersible Quartz, Titanium