Fish disease and sickness -
Both wild caught and farm raised fishes carry parasites/bacteria which
usually does not cause significant harm in normal water conditions.
This is the same as us humans carrying millions of bacteria and dust
mites on our hair and skin, without serious effects. However, these
'harmless passengers' can cause serious trouble, when the following
or combinations of the following factors occur:
1. Fish is under stress, causing a lowering of immune system.
2. Poor water conditions, especially sudden changes in water conditions
3. Physical injuries such as cuts, scratches or bites
If left untreated, a single infected fish will pass the infection to
all other tank mates. Over time, your tank becomes a death trap killing
everything in it.
(common aquarium sickness treatment)
Most of the time, parasites/disease are introduced to the tank by new
additions to the tank. The majority of these problem additions will
be fish or plants, while the rest will be aquarium decorations which
have been in infected water. To be safe, always boil non-living objects
which may have been in contact with parasites and diseases before you
add them to your aquarium. This is especially true for pieces of rocks
or wood which you have picked up from a natural setting. Obviously,
we cannot boil fishes before we add them to our aquarium, therefore,
you have to remember the following points in order to aquire good fish:
1b. Avoid aquiring fish which exhibits the following symptoms
* abnormal swimming pattern (such as tailspin, rapid/jerky movement
In a fish shop, it is usually easy to spot problem fishes if you look
at the whole tank without concentration on one single fish. These fishes
usually do not move in tandem with other fishes in its tank.
* signs of injuries to fins and body. e.g. bleeding, ulcers, skin or
Skin/fin tear are usually caused by territorial fish fighting with one
another. In most cases, these injuries can heal rapidly. However, in
such cases we should think about its injuries and why it is injured.
Aggressive fish often fight and cause damage especially in a small enclosed
environment. If only one fish in the tank is injured but the rest of
the fish are relatively injury-free, then that fish may have been picked
upon because it is already weakened by some kind of sickness and the
other fishes have sensed it.
* eyes blurry. Popeye or cloudy eyes, or white spots on fins and body.
Fishes which display these symptoms are already sick. Do not introduce
them to your tank. Treatment for fish sickness is available at the bottom
of this page.
(An interesting related article: How to
catch aquarium fish tells you why you should catch your own fish
and how to do it.)
2. In your home aquarium pay attention to your fishes for at least
a few minutes a day. Stressed or sick fishes may exhibit certain unusual
* not eating as usual.
A healthy fish will devour any food gladly. A loss of appetite in the
short term when a fish is introduced into a new tank is normal. This
is due to the stress of new, unknown surroundings for the fish as well
as a new feeding pattern by different keepers. However, if a fish is
to suddenly stop eating in the same tank, it is highly possible that
it is stressed or sick.
* always hiding behind shelters or water plants, being bullied by other
tank mates regularly.
* coming up to the surface to breath regularly, could be a sign of an
over-crowded tank or insufficient dissolved oxygen in the water. (in
the latter, changing fresh water will help)
* gasping for air at the water surface, never swimming down.
When this happens to every fish in the tank, you need more aeration
in your water. If you are not using an air pump but only a filter, adjust
the deployment height or the height of the water outlet so that there
is more surface agitation, causing more air to dissolve into the water.
If this sympton is happening to only one fish in the tank, watch closely
at the eyes for cloudy eyes. Most fishes gasp for air at the surface
when they are turning blind. It may be because they are less likely
to bump into submerged decorations and plants. Also, it is partly due
to them being sick and is finding more difficulty breathing.
3. Ensure the water condition is kept to the ideal level.
*Check for presence of ammonia and variation in pH at least once a month.
*Change the water regularly, making sure that the temperature and pH
level is similar.
*It is best never to change more than 50% of the water at one time.
*Avoid cleaning your biological filter all at once. If there are several
filter components, alternate cleaning each component. Also, it is best
not to clean your biological filter under the tap due to chlorine which
can kill off all beneficial bacteria. It is advisable to syphone water
from your tank into a pail, and to use that water to clean your filters.
The following are common diseases that happen to freshwater aquarium
1. White Spots (Ich)
2. Fin Rot
4. Cloudy Eyes
5. HITH (Hole In The Head) (mostly happens to
6. Blackening Fins and Body