The main reason discus are considered difficult
is their susceptibility to disease. Though keeping discus in not as difficult as
many think the fact remains that many hobbyists have more disease problems with
discus than with other common aquarium fish. Therefore, the discus keeper must
surpass the average tropical fish keeper in the skills of preventing,
diagnosing. and treating diseases.
PREVENTING DISEASE
It is best to avoid disease rather than to have to cope with it, because many
disease problems are difficult to diagnose, and some disease problems are
difficult or impossible to treat at all.
Proper disease prevention techniques will save
you headache and heartbreak, because you can keep many diseases out of your
aquarium in the first place if you follow a few rules.
• All new fish, including discus and any fish intended to be kept with discus
should be kept in at least a three-week quarantine for observation for signs of
disease which should be treated accordingly. By the end of this period, and if
you are absolutely certain that the fish is free of the most common discus
ailments and eating a normal aquarium diet, you may then transfer them to the
display aquarium.
• The next best thing you can do to prevent disease is to maintain
consistently excellent water quality. It is critical to maintain ammonia and
nitrite levels at zero, and nitrate below 40 ppm (ideally below 20 ppm).
Though a particular pH and water hardness is not critical, it is important to maintain these parameters at constant levels. It is possible to maintain healthy discus at anywhere below or above what is ideal in pH and hardness, but you will not be very successful if the pH in your aquarium constantly fluctuates. Especially the temperature of the aquarium water, which should be kept absolutely stable at a temperature between 82-86°F (27-30°C). A quick temperature drop of 3°-4°F can bring on a parasitic infestation.
As organics accumulate in mechanical media, they decompose. Bacterial decomposition processes suck dissolved oxygen out of the water, and can cause consequential decreases in dissolved oxygen levels. Dissolved oxygen levels can be kept higher by keeping accumulated wastes in the aquarium at a minimum, and by faithfully cleaning mechanical filtration media.
• Well-fed fish are usually healthy fish. If you are careful to feed your
discus a varied diet, based on highly nutritious food, your fish will
demonstrate much of their natural disease resistance.
ACCESSORIES
• There are a few more pieces of filtration equipment that can be immensely
useful for preventing disease problems. ULTRAVIOLET STERILIZERS are used to kill
bacteria and some free-swimming parasites in aquarium water and could therefore
be a very useful component in your set up. OZONIZERS do the same job and are
also a means of chemical filtration through oxidation of dissolved organics. It
also increases the dissolved oxygen content of the water. But the user must be
careful when using this equipment because if not used correctly, ozone is
damaging to gill tissue and discus' sensitive skin. We should also mention here
that DIATOM FILTERS are able to filter many of the larger free-swimming
parasites out of the water, so diatom filtration can be considered a usefull
mechanical aid in combating some parasite problems.
-THE DISCUS KEEPERS MEDICINE CHEST
Here are the medications I keep on hand at all times and in sufficient quantities for those disease problems that typically plague discus. Note that several of these medications are available only from a veterinarian or a regular drug store, so you won't find them at your local pet store. If you don't want to go to the trouble of getting medications from a vet or drugstore, there is usually an alternative treatment available from pet stores, but it may not be as effective. Also note that whenever you purchase a commercial medication from a pet store, you should follow the dosage directions for that particular preparation, even if they conflict with the dosages that follow here.
Formalin is a 37-40 percent solution of formaldehyde gas in water, and Malachite
Green is a dye. They can be used separately, but a mixed solution of formalin
and malachite green has a synergistic effect (more effective than either
medication alone) in controlling both external protozoans and monogenetic
trernatodes. This combination is readily available in local fish stores, though
a breeder or large scale hobbyist can make up a stock solution by adding 1.4
grams of malachite green to 380 cc of 37% formalin. Formalin is used in a
one-hour bath at a dosage of I ml stock solution per gallon (20 drops/gallon),
or in an established aquarium at I ml stock solution per I 0 gallons (2
drops/gallon) every 3 days for three total treatments. The one-hour formalin
bath is excellent for body and gill flukes, and the 3-day treatment is the
treatment of choice for common protozoans such as costia, chilodonella and other
agents of slime disease. Malachite/formalin is the treatment of choice for
"ick". Formalin drastically reduces dissolved oxygen levels, so
aeration must be provided via an air stone during the one-hour bath. Remembering
that the capacity of water to hold dissolved oxygen decreases as the temperature
increases, formalin should never be dosed into an aquarium if the water is above
80°F (26.6°C) without additional aeration. In addition, a one-hour formalin
bath should never be used on fish with sores or ulcers, as the formalin will
cause the fish to lose body fluids and dehydrate.
Dylox (Trichlorofon)is an organophosphate,
available as an over-the-counter preparation under such names as LifeBearer,
Di!ox, Clout, Masoten and Anti-parasite. This drug is effective against
protozoa, gill and body flukes, and to a lesser extent, Capillaria, but is
highly stressful and potentially toxic to fish. Dylox treatment will make the
fish nervous and will increase their respiration. Dylox. a neurotoxin, is very
injurious to humans, and it is easily absorbed through the skin and mucous
membranes. So you must be very careful not to inhale it or handle it without
protective rubber gloves. Dylox is very effective, but some strains of body
fluke have developed a resistance to it, so its usefulness may vary.
Praziquantel is available from veterinarians under the trade name Droncit.
Flukes on wild-caught discus will he immediately killed by dylox, but
tank-raised discus may carry flukes that have developed a resistance to dylox.
Praziquant.el is used in a 1-2 hour bath at a dosage of 15-20 ppm (rng/L) or
60-7 5 mgs. Per gallon. It can also be dosed through food at 20-150 mgs/kg (2.2
lbs.) of fish weight for nematodes (Capillaria). Praziquantel is very safe to
use; overdosed fish display uncoordinated swimming and irregular breathing. Both
symptoms disappear when returned to unmedicated water.' Praziquantel is
ineffective against fish lice (Argulus) and anchor worms, for which dylox is
still necessary. Praziquantel also cannot be used in an aquarium with a
functional biological filter, so use it only in a 1-2 hour bath or in food.
Metronidazole is available as the prescription drug Flagyl and in aquarium
medications with the trade names Hexout and Hexamit. Metronidazole is used to
treat the notorious internal flagellate protozoans Hexamita and Spironucleus.
Metronidazole is administered at 250 mgs. per 20 gallons (75.6L) every other
clay for three treatments, with 50% water changes in between. The medication is
absorbed through the gills. As the fish improves, a food medicated with
metronidazole (I gram per 4 ounces of food) should be given. The sugar base in
metronidazole tablets may produce a bacterial bloom, so water changes every
second day are recommended.
Fenbendazole is available through veterinarians under the trade name Panacur. It
is very useful for Capillaria and other internal nematode worms. It is a very
safe medication to use in either of two ways:
It can be dissolved in a frozen gel food at I percent by food volume (1 gram per
4 ounces of food), or if the fish has stopped feeding, "tubed" with a
syringe directly into the fish's mouth at 75-100 mgs per kg. (2.2 bs) of the
fish's weight. Panacur is most commonly available in a 10% suspension, so the
above dosage should be multiplied by 10 when using a 10% diluted solution. One
large medicated feeding or two small ones are sufficient to rid the fish of
nematodes, but the fish should be treated again after 3 weeks. Often fish stop
eating when infested with internal nematodes, so direct injection into the
fish's mouth maybe necessary. Other medications for this purpose are Ivermectin,
Fubendazole and Flubenol but the proper dose cannot be recommended at the time
of this writing.
Potassium Permanganate
An old-fashioned cure, but still one of the best for external fungus is
potassium permanganate. A daily bath in a 1:5000 dilution by weight (about 75
mgs./gallon) of purple crystals in water is very effective against fungus.
Always mix a fresh solution before use, as the solution quickly deactivates. The
container used for the bath must be very clean, because potassium permanganate
is an oxidizer and will be "used up" by organics in the container
before the solution can be effective against fungus.
Sodium Chloride (Salt)
Certainly the oldest medication for fish diseases is none iodized cooking salt.
I tablespoon per gallon of water will often cure mild cases of fungus in two or
three days, and discus can handle the added salt for the brief time necessary.
This level of salt will kill aquarium plants and most snails, hence a separate
treatment aquarium is necessary.
Ceftazidine
Used by doctors under the trade name Tazicef. Ceftazidine is extraordinarily
effective for treating bacterial infections. Gaping, bloody wounds that are
thought untreat able are oten reduced to scar tissue several days after
treatment with ceftazidine. Inconveniently, ceftazidine is generally used as an
injection in the epaxial mustlejust below the dorsal fin. The dosage is one
injection every third day for a total of three injections at . I mL of
reconstituted solution pe(kilogram (2.2 lbs.) of body weight. Ceftazidine is
very expensive, so it usually is not used as a bath. Also, because ceftazidine
deactivates rapidly after reconsitution, the unused solution should be frozen.
Nitrofurazone is the antibiotic of choice for most bacterial problems such as
cloudy eyes, eroding fins and tails, external bacterial infections, and minor
abrasions and wounds. Nitrofurazone does not inhibit nitrifying bacteria, so
fish may be treated in the display aquarium if necessary. An additional benefit
of nitrofurazone is that it may be safely triple-dosed in difficult cases.
Nitrofurazone will color the water yellow during treatment, but this color will
quickly disappear after filtering through activated carbon. Dissolve
nitrofurazone in aquarium water at 50 mgs per gallon every other day for seven
days (four treatments) with a 25% water change between dosages. The level of
medication in the aquarium will build up over the course of the treatments
despite the water changes. Nitrofurazone may also be added to food at 6 mgs. Per
4 ounces (.05 mgs/gram) of food twice a day for nine days. If you find that
nitroturazone is ineffective against a particular bacterial problem; try a
preparation of tetracycline according to its manufacturer's recommendations.
Furazolidone is an antibiotic closely related to nitrofuarazone . It can be adminstered in food to fish at a dosage of .05 mgs per gram of the fish's body weight for six days. Several commercial preparations are available that combine nitrofurazone and furazolidone. One such commercial medication is Furan II and another is Furazone Light. A capsule of This is the most dreaded disease of discus, but proper quarantine treatment for all new fish lessens the threat considerably. Hexamita are intestinal flagellated prntozoa that attack the lower intestine. Hexamita iniestat ions are often confused with a syndrome known as "Head and Lateral Line Erosion" which is caused by environmental conditions. When infested by Hexamita, the fish often hide in the corner head down, become thinned at the head above the eyes, blac ken in color, swim backwards, and excrete slimy white feces. The slimy, mucous feces are the first symptom of Hexamita, even while the fish are still eating and behaving normally. Fortunately, a sure treatment for Hexamita has been validated by the experience of many aquarists through metronodizale, which may be dispensed by dissolving in aquarium water, mixing with food or force feeding through a tube. Note that because of intestinal damage, the fish may not begin eating for seven to ten days after elimination of Hexamita.
COMMENTS THAT MAY HELP YOU.
Spironucleus is similar to Hexamita, as is
Octomitus, and it produces similar symptoms. For all practical purposes, the
aquarist may consider Spironucleus and Hexamita as the same condition.
Slime Disease
Costia and Chilodonella are parasites easily
resisted by healthy fish. Weakened fish are susceptible, though, arici show
patches of excessive mucus, rapid breathing, lethargy, and then slough ing off
of skin in patc lies. There is a gray coating on the body, often accompanied by
bloody patches on the body. Fungus often follows.
Body Flukes
Monogenetic tremnatodes are parasitic worms
that require no intermediate host, so they can rapidly multiply in an aquarium.
These livebearing parasites often attack discus. They reproduce rapidly, with
each fluke containing within its body three more generations. The embryo within
a mature fluke already contains within it another embryo, which already contains
another embryo! A mature fluke can produce about a million descendants within a
month. Body flukes feed on the skin and blood of fish. Each individual fluke
does little damage, but massive populations are devastating to fish. Healthy
fish in a healthy aquarium are usually able to resist serious damage. Flukes
cause open skin wounds that become infected with bacterial, further compounding
~he problem. Worms removed from the fish can live up to ten days without a host.
Symptoms include twitching and scratching, but with the absence of white dots
typical of "ick". In heavy infestations, minute red dots appear on the
body and fins, and fins may fray slightly.
cont.
Gill Flukes
Another monogenetic trematode. This egg laying parasite can survive up to 8 days
without a host fish. Fish infested with gill flukes often breath out of only one
set of gills at a time. Discus with gill flukes also rut) and scratch themselves
against objects in the aquarium in an attempt to dislodge the flukes. The
afflicted discus also often exhibit "spitting" behavior.
Capillaria
Capillaria is introduced into the tank with wild-caught fish. Mild infestations
are tolerated well by healthy fish, but a serious case emaciates the dorsal
ridge, and then the rest of the body. The fish also becomes seclusive, and
eventually stops eating. Often the stomach bulges '~vith worms, not food. The
infection spreads as Capillaria eggs in a fish's feces are ingested by other
fish. The eggs will not hatch outside of a fish so good aquarium care goes a
long way toward prevention.
Hole in the Head
"Hole in the head" or Head and Lateral Line Erosion syndrome (HLLE)
begins as small pits on the head and face, usually just above the eye. If
unchecked, HLLE causes cavitation on the head, with progressive erosion along
the lateral line. Astonishingly, the fish lives through the syndrome, in some
extreme cases appearing like a corpse while swimming around as if nothing is
wrong. Eventually bacterial infections in the bared tissues lead to death. A
source of great confusion among discus keepers has been the association of
"hole in the head" disease with Hexamta. Hexamita has never been found
to cause "hole in the head" disease. HLLE is attributed to a
nutritional deficiency of one or more of these essentials: vitamin C, D, calcium
and phosphorus. This deficiency is assumed to be the result of poor choice or
variety in food, lack of partial water changes, or overfiltration with chemical
media such as activated carbon.
EUTHANASIA
There are those cases when a fish does not respond to treatment, or a fish has
acquired an untreatable illness, or a fish is so damaged or wounded that its
death is inevitable. In such cases the fish can be placed in a sealed plastic
container with enough water for it to stand upright, and this container is
placed in a freezer, where the fish's metabolism simply slows down and stops.
This is humane and the this is demonstrated by the fact that the fish can be
found several hours later frozen upright, and not in a contorted position.
Alternately, the fish can be given the anesthetic MS222 at 500 mgs per liter in
a small bucket.