FISH DISEASE ARTICLES: HEXAMITA: Internal and external
The external form of Hexamita is referred to as: Hole in the head
disease. This disease affects susceptible fish such as discus,
angelfish and oscars, which seem to be the most popular carriers of
this problem (note that this disease may affect all fish).
This disease usually starts out as a small "pimple" on the head, and
as the condition proceeds in severity, ends up to be a very large
sore causing lesions in the epithelium and... eventually ending up
in death of the fish. Sometimes you are able to see small
white nodules, sticking up out of the sore. The lateral line
is also another area where this parasitic protozoan can be seen.
This disease is best treated early on with Metronidazole, or
something stronger like Quinine Sulfate.
The internal form of Hexamita are flagellated protozoans found in
the gastrointestinal tract of a wide variety of fishes. They
frequently infect discus. Spironucleus may be a distinct
organism from Hexamita, as it is longer and possibly more sinuous,
but for practical purposes, both organisms appear to cause similar
clinical responses. These parasitic protozoa are very motile. The
flagella are usually not easily seen. Many times infections
are not apparent. In angelfish, discus and gouramis, the
disease is characterized by poor condition, weight loss and death.
The fish may also show excessive nervousness, turn dark in color,
and hide in the aquarium.
Again, Metronidazole is the drug of choice for internal
Use 1 teaspoon per pound of food (frozen food is preferred).
Thaw the food and mix the Metronidazole into it. Return the
food to the freezer, and once frozen you are ready to start the
treatment. Feed it to the fish once a day for a minimum of ten
days. Do not feed the fish any other foods during this
treatment. The treatment may take longer according to
the condition of the fish, and the severity of the disease.
Metronidazole is for internal Hexamita, and the Quinine Sulfate
is for external Hexamita only.
Dr. Gary Aukes; Pharm D, Dr. Brian Aukes; PhD., and the staff of National Fish
Fish Disease Articles
Items that can be used to treat the diseases listed
in this article include: