The Goldfish Sanctuary
The Quarantine Tank
A quarantine tank serves two purposes in fishkeeping. First, it is a
good idea to quarantine new fish in a separate tank for two weeks before
moving them to the main tank. This helps to ensure that the fish is
before he is brought into contact with your other goldfish.
Another reason for having a quarantine tank is in the event that your
fish has become sick. A sick fish is often best separated from the main
tank to eliminate the chance that he will infect the others. Once there,
the fish is treated until well, then returned to the main tank after a
few more days of observation. Although it is true that sometimes you will
want to treat the entire main tank, very often it is most beneficial to
isolate just one or two fish for treatment.
Benefits of using a Quarantine Tank for Sick Goldfish
Risk of infecting tankmates is reduced
Main tank is not greatly disrupted
Biological filter will not be harmed by medications
Live plants will not be harmed by medications
Less medication needed if quarantine tank is smaller than main tank
Fish will not be harassed by healthy tankmates
Setting up the Quarantine Tank
A quarantine tank is often smaller than a regular tank, and because
it is to serve only as a temporary home, this is acceptable. You must
obtain a small tank. A ten gallon tank will be acceptable for one or two
fish. You will also need an airpump and airstone, plus airline tubing.
Aeration is especially important in a quarantine tank because the size
of the tank is often smaller than usual, and medicines sometimes take
out of the water.
Lastly, find something to cover your tank with so that the fish don't
jump out. Nothing else is needed. The quarantine tank should be relatively
bare. This will make cleaning much easier. Your fish may be reassured by
the presence of some plastic plants or hiding places, however. You may
wish to include some of these. Lead anchors are sold that can be used to
hold a plastic plant in place. Also, since the fish is reassured by a dark
bottom, you can place the tank on top of a dark mat or piece of cardboard
if you wish. This will show through the bottom of the tank.
If you do decide to use a filter in the tank, make sure there is no
activated carbon in it.
Place the quarantine on some steady, flat surface which will be able
to hold the weight of a full tank. It is a good idea to put some water
from the main tank into the quarantine tank to avoid stressing your fish.
If your main tank is very big, this will be no problem. If your main tank
is somewhat small, adding just a little of the water will also help. Take
water from the top of the main aquarium. This water is always the
When your quarantine tank is full, attach the airstone to the airpump
with the plastic tubing. Then place it in the tank and weigh it down if
necessary so that the stone is at the bottom of the tank. Next, add any
decorations like plants or hiding places. Make sure all of these are
If you decide to install a small filter, do so now. It will help to
keep the water clean. If your purpose is to treat sick fish, don't add
any filter carbon. If you are using the quarantine tank to observe new
arrivals, carbon may be added.
Note - any equipment used for the quarantine tank should not be shared
with the main tank. This aviods the possibility of passing infection to
the main tank.
Moving the Fish to and from the Quarantine tank
Use a clear, clean plastic bag to catch the afflicted fish. Using a
net is not advised (it could injure your fish). If the water in the
tank came entirely from the main aquarium, you may place the fish into
the quarantine tank immediately. However, if the water in the quarantine
tank is different in any way from the water the fish was previously in,
or if this fish came from the petstore, a period of acclimation is needed.
Acclimating your Goldfish
Tie the bag shut but leave plenty of air in it. Float the bag in the
new tank for 15 minutes. Then, over the next few minutes, add a little
more water to the bag from the new tank. When this process is complete,
open the bag and let the fish swim into the tank.
Observing Fish in Quarantine
Remember that moving a fish to a new tank can be in itself a stressful
experience, so you will want to keep a close eye on quarantined fish.
fish disease is not yet an exact science, and usually one medication is
used to treat several similar ailments. Further, it is not always easy
for a beginner to accurately diagnose a fish's ailment. Because of these
facts, the best way to determine your fish's condition is careful, patient
observation. Don't forget to stay in touch with your local vet or
especially if further complications develop.
Keeping the water clean is important for several reasons. Most
because goldfish produce more amonia than many other fish, they can
poison themselves when kept in a tiny tank. Daily partial water changes of 20-25% are suggested
during quarantine. (Filters with
activated carbon often take medicine out of the water, and can't be used
when treating sick fish). A water change is best done 1 hour after feeding
time, for this is when fish are most likely to expel waste.
Some medications can be used together, but some cannot. Read and follow
all instructions carefully, and contact your petstore when in doubt. If
one medication fails to work, and you wish to attempt another which is
not compatible, be prepared to do several days of partial water changes
after you finish the first treatment before attempting a new medication.
This will help to dilute the original medicine and minimize the chances
of a negative reaction. If your fish is in bad shape, however, you may
have to add the new medication sooner, in which case you should do about
a 90% partial water change before adding the new medication.
When the fish is cured, keep him in the quarantine tank for another
3-5 days to ensure that the condition does not recur. When at last it is
time to place the fish in general population, catch the fish in a plastic
bag and go through the acclimation procedure (see above). Try to remove
as much of the quarantine water as possible (replacing it slowly with
from the main tank) before setting the fish free into the main population.
Closing Down the Quarantine Tank
When your quarantine tank is once again empty of fish, it is time to
close it down. Because medicines and diseases may have been present in
the quarantine tank during the time it was up, it is important to clean
it and all equipment very well before storage. If you are not absolutely
sure that your tank is free of disease, you may want to continue
the bare tank for a few days to make sure it is sterilized. (Another way
to kill freshwater diseases is to add a high concentration of salt to the
water... freshwater bacteria or fungus usually die in a very saline
Just make sure there aren't any fish in the tank when you attempt this
precaution!) Any other equipment that may have contaminated can also be
placed in the tank. Continue to aerate the tank during this process...
discard airline tubing when the process is complete.
Drain the tank completely. Rinse all the equipment well in hot water
several times. Salt makes a good cleaning agent in place of soap or
When all of the items have been well cleaned and rinsed, it may be allowed
to air dry. Setting the tank and equipment in direct sunlight for 4-5
days is the most effective tecnique. If you do decide to wipe it clean,
paper towels are suggested over cloth towels. The latter may contain soap