THE UNWANTED TANK GUEST
By Jim E. Quarles
If you keep discus fish sooner or later you're going to have this
unwanted guest appear in your tank and cause your beautiful discus all
kinds of grief. I am sure you have seen programs about Americas TEN MOST
WANTED CRIMINALS by the F.B.I.!
Well, Mr. Hexamita is either # 1 or close to it on the unwanted list
for discus diseases. But despair not, there is a way to lock this criminal
out of your fish.
This is a parasite caused problem. A flagellate protozoan, called
Hexamita, also known as Octomitus. The obvious symptoms are easy to spot.
Small holes appear in the body, especially the head region, which develop
into tubular eruptions.
Most of the time yellow, strings of mucus will be seen coming from the
lesions. This leads some hobbyist to mistake this parasite as a worm
infestation. Lesions may also develop at the base of the fins and near the
Photo credit to Tetra Press
Affected fish will go off their food and become hollow bellied, this
increases the weakness of the affected fish and other diseases may develop
in short order. Hexamita exists as a low level infection in the intestines
of cold water and tropical fish. It should be noted that it is noticed in
Quite a few factors may come into play with causing the onset of this
disease, over crowding, low oxygen content of the water, when you find
this disease most often you will also note unhygienic conditions in the
tank. Even quick changes in temperature and poor diet can cause the latent
parasites to multiply and develop the acute symptoms.
It is my feeling also that a lack of vitamin C & E play a part in
the development of this problem, as well as environmental factors.
TREATMENT AND CONTROL
The best way of treating hole in the head disease is with medicated
food. But it is sad to say, affected fish often stop feeding and it is
difficult to mix medicated food on a small scale.
However there are a few drugs that can be mixed into the treatment
tank's water that have proven effective, Dimetridazole and Metronidazole,
both of which are only available with a veterinarian's prescriptions in
For long term control it is important to quarantine all new stock, and
give appropriate preventative treatment and eliminate the factors which
are known to bring the onset of this disease. I would recommend fresh
vegetable matter in the diet and removing activated carbon during
LATENT INFECTIONS IN GENERAL
Most people fail to realize that most apparently health fish are
usually carrying a wide range of potential fish pathogens in or on their
bodies at all times.
These are latent infections that do very little harm, but their
importance to the fish keeper cannot be over looked. Even under the best
conditions and with the healthiest fish, lurks pathogens just waiting to
cause problems for the less than vigilant hobbyist.
I hate to bring this matter into this article, but it must be said or
go unnoted. Breeding hybrids can interfere with and weaken the immune
system of all fish. This hybridization is most noted in the current crop
of discus being kept by most discus hobbyist. So it is possible that the
fancy color morph's, desired by so many are going to be victims of this
and other diseases to a much greater degree than the wild stock of