Ichthyophonus (Ichthyphonus) fungi are one of the more devastating aquarium diseases. It is nearly impossible to treat, however it is easier to prevent.
This disease may be more common than many aquarists realize as identification is often very difficult with the proper scientific instruments and a Necropsy of infected tissue such as the heart or brain.
A few possible outer symptoms include:
*Ulcerated small nodules in the skin
*Bulging eyes (from pressure exerted from the infection in the brain)
*Loss of color (similar to Neon Tetra Disease)
*Loss of energy (due to the infection in the heart)
*Whirling; this is a very common symptom that unfortunately usually is one of the final symptoms due to infection in the brain (although this symptom can appear early and be the first symptom)
*Sudden cooling of the water can be allow this disease to go systemic as Ichthyphonus fungi are generally more virulent in colder waters, so this can also be a "symptom" since actual tests are impossible to conduct in live fish (see lower in the article).



Ichthyophonus generally affects fish as an internal fungus , often attacking vital organs such as the liver, kidneys, brain and also the muscles on occasionally. The result is often a deteriorating fish that often stops eating (making medicated foods useless), swimming in circles (loss of equilibrium caused by the infection invading the brain), and loss of color and scales.


The above picture shows the infected heart of an Alaskan Salmon.

Potential treatments are Methylene Blue Baths, increased salt levels (for fish that will tolerate this) of from 1 -2 tablespoons per 5 net gallons. Some Organic Treatments such as Pimafix , Kanamycin combined with good electrolyte and calcium levels measured by a GH over 100 ppm can help as a cocktail. A Medicated Wonder Shell would aid this cocktail by adding more anti fungal treatment along with adding important electrolytes and calcium. Other measures for possible treatment (or more to check the spread) are heat as Ichthyphonus fungi are generally more virulent in colder waters, so raising temperatures above 82 F (28 Celsius) can at least aid in checking the spread.

However all the above is often in vain, with the one bright spot that these procedures along with UV Sterilization will often check the spread of this disease. Other important preventatives is too remove suspected fish to a quarantine tank, in fact I strongly recommend this (or simply euthanizing them) as this is commonly spread through the eating of infected fish’ waste by otherwise healthy fish.

Prevention of Ichthyophonus is definitely the best cure.
Here are a few preventative steps:

*Quarantine or at least give 30 minute medicated baths in Methylene Blue or Potassium Permanganate.
*Keep optimum water parameters for the fish you are keeping whether FW or saltwater.
For freshwater this includes ammonia/nitrites at 0, nitrates below 50 ppm, a stable pH, and proper mineralization for the fish kept (a GH of at least 100 ppm, often higher for many fish).
*Regular cleaning procedures
*Possibly UV Sterilization
*Treatment with Malachite Green/Acriflavin/methylene blue based products (such as Medicated Wonder Shells or Aquarium Pharmaceuticals Fungus Treatment) after suspected Ichthyophonus carrying fish die or are removed.

Please read this article for more about aquarium disease prevention:
“Aquarium Disease Prevention”

Please read this article for more about studies of Ichthyophonus in Salmon:
“Ichthyophonus Disease”