Diseases and Cures
In nature, all creatures are carriers of diseases to some extent.
Some are infectious, while others are not. It depends on various factors
and activities. Differences still exit between nature and in the aquarium,
even though man may have artificially provided the best of conditions. An
Arowana, like any other creature, can easily be infected once its
resistance to disease is low.
Other than insufficient care,
bacterial and parasitic contaminations are the main contributing factors
when an Arowana is ill. The followings are brief descriptions of some
diseases and their corresponding cures.
Condition and Treatments
Bad water quality, decaying leftovers, due to improper
feeding and excessive excrement make the water quality bad, leading to
high level of nitrate, ammonia, and decreasing the level of dissolved
oxygen in the water.
When an Arowana is still
growing, it needs sufficient space, together with proper nutritions. The
length of the aquarium should be at least 3 times the length of the
Arowana. Gills may be weak if swimming space is not sufficient.
In the early stage, gills cannot open and close
smoothly with each breath. There are also signs of external tissue growth
near the gills. The hard covers of the gill will tend to collapse,
exposing the inside of the gills.
The condition will worsen if not
treated. The Arowana will have difficulty in breathing; often raising it's
head above the water to breathe. It will also soon stop eating, bacterial
infection will set in, causing the gills to malfunction and the Arowana
Incipient stage. When the Arowana
breathes irregularly, change approximately 20% of the water every 2 to 3
days. Use air pumps and air stones to increase the level of dissolved
oxygen in the water.
In the very serious stages, the gill tissues
are totally sclerotic. An operation is necessary to have the infected
a. Wounded cornea infected by
b. Bad water quality or nitrogen in the fish's body
It usually happens to one of the eyes. At the
beginning, the eye is mistily shaded. In later stages it's become blurred.
In the end, the affected eye swells with white cotton-like cones growing
outward. The Arowana can possibly die if no effective cure is applied.
When the eye is mistily shaded, change 1/3 of the
water in the aquarium. Add some raw salt or sea-additive with a
consistency of 5%. Keep the temperature at 30-33 degree C (86-91 degree
F). Observe for two days, if it does not get worse, the only thing to do
is to change 1/4 of the water every 3 days and adding raw salt until it
heals. If there is worsening in condition, medication should be applied.
Put in some soluble medication such as aureomycin, penicillin or other
dedicated medication for fishes. Use the dedicated medication according to
given instructions. When medications are in use, raise the temperature by
2-3 degree C and observe carefully.
It takes about 3-5 months for
the Arowana to heal in the eyes. Gradually stop the usage of the
medication if the eye does not swell anymore. The iris will look smaller
after healing but functionally this is not a problem for the fish.
White spots (Ich)
White spots or Ich is very common in
fishes. This disease is caused by a ciliate(Ichthyophthirius multifillis).
Which reproduces very rapidly under the right condition. At 25 degree C
one monocye can reproduce itself into more than 3000 individuals per hour.
As the temperature goes up, it will slow in reproducing and eventually
Ich lives on the surface of the Arowana when it
is low in resistance to diseases. It also absorbs the fish body fluid to
reproduce and this is seen as the white powder-like cyst.
As the name suggests, at first white spots appear on
the fins of an Arowana. Then it spreads all over the body. The Arowana
will itch and rub itself against the wall or the bottom of the tank to
stop the irritation. It will begin to lose its appetite and ulcers may
form. Finally the gills don't function properly as the infection becomes
heavy and finally can cause death. Prompt action should be taken once
symptoms are observed to arrest further development of the disease.
a. Add some salt in the water consistency of 1%
b. Add 0.8 gram of quinone vitriol per 100 liters of
Raise the temperature 2-3 degree C higher after adding the
medication of choice. Turn the air pump up to allow more dissolved oxygen
in the water. Make sure Arowana obtains enough nutritions during treatment
to strengthen the resistance to diseases. Be sure to disinfect the
aquarium with potassium permanganate (KMnO4) when the Arowana recovers.
It is also called cone scales. Young Arowana
are more easily infected than adult Arowana.
sudden change in water temperature & change seasons
b. Poor water quality
At the beginning,
only few scales (5 to 8) are a little warped with congested roots. If
attention is not immediate, the scales become bent and swollen. This
raising of the scales will reduce the effectiveness on protecting the fish
from invading pathogens like bacteria. The affected scales will finally
drop off thus exposing an area on the body and increases the
susceptibility of bacterial attack. This will result in ulceration and
finally death in many cases.
Before the situation
become worse, add a kilo of raw salt or sea-additive or refined salt in
every 100 liters of water. Keep the temperature at 32-34 degree C (89-93
degree F). Change 1/4 of the water every 3 days. Warm the water with a
heater before adding it into the aquarium. If the affected area is large,
put some antibiotic in the water to prevent infection and other diseases.
Decay in Gills
Gill decay is caused by microscopic oval
flagellate, not visible to the naked eye. It lives on the inside of the
gill, absorbing nutrients for it's own division. Infection is especially
dangerous at around 25 degree C as the rate of reproduction is very fast.
Bad water quality or a long interval between water
The Arowana breathes heavily and gulps air.
Body color fades away.
The same treatment as with
The fungus lives in the
Arowana's wound, it has a light grayish coloration.
Cotton like fabric, which is the fungal, can be seen covering the
wound. The Arowana becomes unstable when swimming and has a tendency to
rub its body to stop itching. It can die from extreme physical weakness as
a result of refusing to eat or due to secondary infection by bacteria
a. Add some salt in the water to the
consistency of 1%
b. Apply disinfectant to the wound or add 4-5 drops
methyl red with a consistency of 5% in every 100
water. Another alternative is the use of
malachite green but be very
careful as this is poisonous
in higher doses than recommended.
Apply potassium chromatic solution of 1/30000 unit for 3
d. Use dedicated medication for fishes.
Ascites is usually found when the Arowana is young. Probably
caused by decaying baits or by swallowing the pincers or fish bone, which
could hurt the internal organs. Once this happens, wounds will be infected
by vibrion and cause ascites.
At the beginning, the
Arowana suffers from stomach flatulence; anal region becomes reddened and
swells. When water cannot be expelled from the body, its swim bladder will
be squeezed by the stomach. Thus, the Arowana cannot balance itself in the
water with the head pointing down.
The ability to
cure ascites is low. However, it is worth trying for an Arowana to take
antibiotic or sulphonamide orally. Shorten the period between water
changes and raise the temperature to 2-3 degree C.
Also called red erysipelas, it is almost incurable in Arowana. It
usually happens while the Arowana is young due to malfunctions of the
The infection mostly happens near
the tail. It begins with red dots. Later the infected areas swell and tend
to warp. Finally the Arowana will die of ulceration as secondary infection
Try to raise the water temperature to 36
degree C (97 degree F). Give some antibiotic orally to your Arowana in
addition to medication in the water. Do a 1/3 of water change daily adds
raw salt or sea-additive of consistency of 5% and observe carefully.
Living baits used to feed Arowana are the
usual parasite carriers. Other common external parasites are fish louse
and anchor worm.
Fish louse (Argulus Spp.)
Fish louse is from
the crustacean family. The body is about 3-5 mm in length with flat shell,
thus it can be seen with the bare eye. It attaches itself to the fish via
a sucking device, the oculus. Its has needle like structures that anchors
onto the Arowana body and withdraw the body fluid of the fish, making the
body less lustrous. The Arowana will rub their body against the tank walls
to get rid of the irritation caused by the fish louse.
It lives on the fins or in partially embedded into the fish body.
Spike about 1 cm long, grows on it's head which are used to absorb
nutrition directly from the Arowana's body. The infected area swells and
becomes ulcerated. An infected Arowana becomes impatient with less
appetite and begins rubbing its body in a bid to get rid of the parasite.
Disinfect with organic phosphoric acid of 1/5000
000 consistency or use 2 grams of potassium permanganate (KmnO4) in every
2 liters of water. Fish louse will also fall off after the Arowana is pit
in higher consistency salt water for 3 minutes. Be sure to allow enough
oxygen in the water. For anchor worm use san-Iv-song solution at 1/1000
000 consistency (equivalent to 1 gram per 100 L). Or use formalin instead,
put 5 ml in every 100 liters of water to kill the Parasites.
Be sure to disinfect the aquarium when the Arowana heals.
Generally, adding salt in the water and raising the water's
temperature are the safest cure with no side effect. Medicine is only used
as the last remedy. When you have to do so, apply half of the dosage of
the normal amount first. Then increase or decrease the amount according to
the state of illness to avoid resistance to the drugs building up in the