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Plistophora (Neon disease): Treatment

Phyllum: Protozoa (Protozoa)

Class: Sporozoa (Microsporidia)

Family: Nosematidae

Cardinal tetra with symptons

The causative agent

All members of the Class Sporozoa (Microsporidia) are parasites. Here we are faced with another disease that is difficult to treat. Specialist texts consider plistophoriasis incurable. But we believe that it is preventable and in very few cases 100% curable.

Diseased fish neon


In general, the disease is manifested by a discoloration in the luminous band of iridescent tetras (see images above), although it also attacks other tetras and fish such as “zebritas” (Brachidanio rerio). This discoloration begins as spots that spread along the lateral line, affecting the muscle mass, where the protozoan resides.

Another notable symptom is that affected fish do not “sleep” at night, swimming incessantly instead of resting near the bottom.

It is also observable (as in other diseases) an isolation of the patients who separate from the school, an irregular swimming, sometimes backwards. Almost simultaneously, and because the infestation is at an advanced stage, it can be seen that the fish swims obliquely, with its head up, trying to recover its position by means of more or less sudden movements. Thinning and sunken abdomen together with discoloration of the luminous band indicate without a doubt the presence of Plistophora hyphessobryconnis and the mere suspicion warrants immediate isolation of all specimens suspected of being contaminated.

Confirmation of the diagnosis can be made with a microscope at 120x magnification, and both those preserved in formalin and live and fresh can be used as material. The parasites are preferably found in the trunk muscles, although they have been located in the kidneys, intestine and other organs. By crushing and by dissociation, samples are taken from said muscles, in which pansporoblasts should be seen in abundance. They can be compared with the illustration if in doubt.



We said above that pansporoblasts have been located in the kidneys, so that when they release the spores from their interior, they are expelled through the urine into the environment, leaving open the possibility of massive contagion. While the spores remain free seems to be the best time to try some medication. Since the commercial formulas have not been disclosed, we suggest the use of half a dose of malachite green (warning: tetras are very sensitive to this product) or Cupric Chloride, in any of the forms suggested in our Table C (Therapeutics). The best thing to do, however, is to take preventive measures by avoiding introducing contaminated fish, avoiding low temperatures (which facilitate the development of this disease) and immediately isolating the fish suspected of being affected.

When it comes to small amounts of fish, and taking into account the reproductive cycle, it could be wise to change the container every 12 hours, taking care that the water conditions are similar from one container to another. The emptied container is disinfected with a strong chlorine solution and after rinsing it well, it will be ready to receive the fish twelve hours later, after preparing the water with a colloidal conditioner and eventually applying a dose of some antiparasitic (to control toxicity).


Treat the aquarium with Metronidazole Aquatic Antibiotics 400MG at a dose of 250 MG every 10 gallons of water until complete improvement, renewing the treatment every 48 hours. Maintain acidic pH (5-6) and soft water. An alternative is to use Tetracycline Aquatic Antibiotics 250MG – at a dose of 500 MG per 13.20 Gallons of water. In addition, very sick specimens should be sacrificed to cut the contagion vector.