It is pretty well agreed-upon that prevention is preferable to treatment for any disease. Surprisingly, aquarists do not often take this approach seriously. As unintentional as it may be, countless animals have been lost due to this negligence. A few well-planned steps of prevention can save a great deal of money and, more importantly, animal's lives.

There are many different steps that can be taken to maintain the health of aquarium animals, and improve their longevity at the same time. Diet, water quality, stress reduction and preventive measures all play important roles. But the practice of quarantining animals is an often overlooked yet crucial step toward prevention of disease. For our purposes, quarantine is defined as a period of isolation, observation and acclimation for newly acquired specimens. When necessary, the quarantine tank can be used for treatment and recovery from diseases or conditions affecting fish.

There are four factors that are instrumental in a successful quarantine: providing sufficient quarantine time, monitoring the parameters, carefully observing the animals each day and keeping accurate notes. The isolation period should last for a minimum of three weeks. If any other fish are added to the quarantine, the "clock" should be reset for all occupants of the quarantine tank. Parameters such as ammonia, nitrite, copper, temperature, pH, alkalinity and salinity should be tested on a daily basis. The fish should be watched closely each day for visible symptoms or behavioral changes that may indicate disease or distress. Recording your test results and making daily observations will help you identify diseases and other problems while they are in their early stages.

I suggest being prepared by always keeping a conditioned quarantine set up and ready to go. The biological filtration can be maintained by adding a little ammonium sulfate or ammonium chloride to the water during periods the tank is uninhabited. Another method is just adding a small amount of food to the water twice a week. However, over feeding the biological filter in this way can result in cloudy, polluted water.

The quarantine tank can be simple, and inexpensive to setup. A 10- or 20-gallon aquarium or container is usually large enough. A heater, thermometer, one or two pieces of PVC pipe to serve as hiding places, cover and something to provide biological filtration is all that is really needed. It is handy to have chemicals, test kits, net or container to catch fish and a notepad nearby. Place the quarantine tank in a location that is out of the normal traffic pattern in your house. People regularly passing back and forth in front of the quarantine tank places added stress on the acclimating fish. Darkening the back, bottom and sides of the quarantine tank can reduce the animal's awareness of activity outside of the quarantine tank thereby reducing stress. Biological filtration can be achieved by using a simple sponge filter and an air pump or by using a small power filter with a bio-wheel. It is usually a good practice to fill the quarantine tank with water from your display aquarium, provided it is of good water quality. Maintain the quarantine tank temperature between 78 and 80F.

With some styles of quarantine, the tank, filters and utensils should be sterilized with chlorine between each use. This can be accomplished by using about a 2% solution of chlorine to water. Leave the tank in the solution a few hours and then drain the water and replace it with freshwater and some dechlorinator. Be sure any traces of chlorine are gone before using the aquarium again. A second sponge filter or bio-wheel can be kept in the sump of the display aquarium as a back up bio-filter. It can be rotated each time the quarantine is sterilized.

When you bring a new fish home, acclimate it to the quarantine water using the drip method to equalize the temperature and water chemistry with the quarantine tank water. This is done by placing the fish with some of the transport water into a container, and then using plastic airline tubing with a knot tied in it to slowly drip water from the quarantine into the container. Take about 30 to 60 minutes to complete this process, then carefully transfer the fish without adding any of the water from the container to the quarantine tank.
When transferring fish, avoid using a net whenever possible. Netting frequently leads to injury to the eyes, scales, mouth, fins and skin of fish. A net can be safely used to corral the fish into a plastic bag or small bucket. When transferring the fish in a plastic bag, turn the bag upside down while holding it closed so the fish cannot fall out and allow the water to drain from the bag into a bucket. Then you can release the fish into the aquarium by opening the bag at the surface of the aquarium water. If you must use a net, thoroughly wet the net in tank water before transferring fish with it. Dry nets are like sandpaper on a fish body.

Do not turn the light on in your quarantine tank for at least a day. Also, do not try to feed the fish during the first 24 hours. The fish need to direct all their metabolic energy toward recovering normal physiological equilibrium, rather than digestion at this point. Once the fish is eating, soak the foods in Selcon™ or Zoe™ vitamins, and add a pinch of Immune Boost™ twice a week while the fish is in quarantine. After the fish has had a couple of days to adjust to captivity, I believe the quarantine period is a good time to acclimate the animal to the regular photoperiod used in the display aquarium. The light can be placed on a timer and kept on about twelve hours a day.

When is a fish ready for transfer to the display aquarium? Generally, the fish is ready when it has shown no signs of any disease or parasite infestation for at least three weeks (keep track in your log book), has no fin or scale damage, and is aggressively eating more than one type of food. Note that this three-week period of perfect health does not include the time it is being treated with medication. If, during the quarantine period, the fish shows any new sign of disease, you must re-set the quarantine clock from that point. Yes, this does mean the actual time a fish spends in the quarantine tank could be several weeks. The alternative is placing an improperly quarantined fish into your display and exposing your established population to the risk of infection. Catching and treating an entire tank full of fish, especially is a reef aquarium, is not a pleasant experience!

You can reduce the stress on the new addition to the display tank by taking a few simple steps. Morning is a good time to move fish so that they have all day to adjust, and dimming the lights for a while when releasing the fish can have a somewhat calming effect. Floating the fish in a see-through container prior to release gives curious tankmates an opportunity to examine each other without exposing them to aggression.

Moving a few pieces of decoration or rock can disorient the established residents just enough to distract them from bothering the new addition. Feeding the fish when the new addition is released into the aquarium diverts attention away from the new arrival long enough for the new fish to get oriented to the surroundings.

There are several approaches to quarantine each with its own advantages and disadvantages. The four primary approaches are display, sterile, combination and hyposaline. There are variations that can be used within each style of quarantine, and the examples given are intended to be generalizations.

Terry Bartelme is a veteran of over thirty years experience with marine aquariums. He has authored more than one-hundred articles for various aquarium magazines including Advanced Aquarists Online, Freshwater and Marine Aquarium, Tropical Fish Hobbyist and other publications.