OVER-VIEW OF FISH MEDICATIONS AND THEIR EFFECTIVENESS
By Jim E. Quarles.
Copper sulfate is a cheap, effective drug that kills many ectoparasites,
but will kill desirable invertebrates and should can not be used in a Reef
Tank. Also much more exacting control must be observed when using copper
in treatments. I do not recommend the average hobbyist use copper sulfate
until they fully understand the need to constantly check its concentration
with a test kit.
Make no mistake, copper sulfate can and often is a fish killer in the
hands of those who treat sick fish with a dash of this and a dash of that.
Formalin ( 38% or 40% formaldehyde in water ) kills many protozoan and
metazoan parasites and fungi, and even external bacteria. A few companies
offer formalin in combination with Malachite Green or copper sulphate.
This should never be used as a prophylactic. It's only appropriate use is
when you are certain the problem is a parasitic protozoan, fluke, or
The use of any cheap microscope, can be used for this purpose. I use 4
to 10 drops per gallon added one drop at a time over a five or six hour
time span. Once the fish show signs of stress, I change half the water and
keep the fish in the bath 24 to 40 hours, before removing to clean
untreated water. Great care must be used when working with Formaldehyde.
Formaldehyde is a powerful irritant of the eyes and mucous membranes of
your nose and lungs. It is also known to cause cancer. So be very careful
in handling this product. Do not use formaldehyde in a confined space, and
make sure you have adequate air flow to keep the vapors under control.
These drugs interfere with the control of nerve impulse transmitted in
invertebrates. These drugs should be used with great caution and
sparingly, as fishes may be adversely affected by multiple or prolonged
They were believed safe for people until neurological symptoms began
showing up in handlers of agricultural products containing these drugs. Do
not contaminate your hands or eat while using the potent chemicals.
The more common types you will encounter go under different names, but
you should know them by, metronidazole, or 2-methyl-5 nitro-1
imidazoleethanol. I am sure you will know it by the name Flagyl.
Organoshosphates are powerful insecticides used in agriculture and are
effective against fish lice, copepoda, leeches, and skin and gill flukes
of fishes. Some of these chemicals can be obtained as mixed preparations
and are effective, but directions should be followed for temperature
control, strong aeration and a water change after treatment.
ANTIBIOTICS AND ANTIMICROBIAL
For treating bacterial diseases there are two classes of drugs: the
naturally occurring antibiotics and the synthetic antimicrobial. We can no
longer use most of the natural occurring antibiotics in fish culture
because overuse in the past has resulted in the development of
Now before you think you're being unfairly highlighted for this crime,
let me correct that impression. It is not the home aquarist (who doesn't
pass his fish around ), but it is the fish farms, and shippers as well as
wholesalers. But even they are not unique in the error of their ways;
physicians and hospitals have over prescribed antibiotics for years. This
has caused drug-resistant microbes to appear everywhere in public health.
We must be careful not to make the same mistake with the synthetic furan
antibacterial, and if they are not over used they should remain effective
in the years ahead.
Nitrofurans are synsthetic drugs effective against all common Gram
negative bacteria of fishes. Preparations in the hobby are nifurpirinol (
Furanace ) Nitrofurazone (Furacyn ), furanone, and furazolidone,
Nitrofurazone is reported as a treatment for fungus is more or less true
since most fungus is typically a bacterial infection know better as
columnaris, or cotton wool disease which can appear fuzzy like a fungus.
Nalidixe acid is another synthetic active agent against Gram-negative
bacter. As a practical matter you will find that most bacterial diseases
in fish are Gram-negative, rarely do Gram-positive bacteria cause problems
in tropical fish.
Antibotics are uncommon on shelves, mostly because the old standby
penicillin, and erythromucins are ineffective against aquarium fish
diseases or as the case of tetracyclines, should always be given in food
rather than dissolved in water. There are a couple of drugs that are new
and resistance is not a problem yet. Neomycin and kanamycin,
oxytetracycline is best used in food. Great care should be used when using
these or any other antibiotic in the treatment of any disease human or
LAST BUT NOT LEAST
Antiworm preparations: Internal worms sometimes occur in fishes, but,
except for some capillaria-type nematodes, they are rarely cause for
concern. Get a cat or dog wormer food from a veterinarian and you can be
sure you are using the right drug and the right dose and delivering it
through the correct route, mixed with food.
Dr.Robert J Goldstein Ph.D.
F.A.M.A Magazine 1998
Handbook Of Fish Health.
Discus Health: D. Untergasser.
Essentials of Microbiology
T.F.H. Publishing Inc.