I know that quarantine is a good way to avoid sick fish. Can you describe a good procedure?
Every time you add fish from a new source, you are adding all the bugs that the previous owner had. Some of these can kill YOUR fish, or perhaps just keep them from raising fry. If this happens, you may have to get rid of your fish, go DRY, sterilize everything, and start over. Bummer.
Through a special arrangement with Lloyd Spear, I am presenting his quarantine procedure.
Dec 11 1998
Quarantine of new fish
by Lloyd SpearOnce an aquarist moves beyond the beginning hobbyist stage, one of the most misunderstood yet most important keys to continued success is the requirement to quarantine new fish.
Now, I know that quarantining new fish is a pain in the neck at best, and sometimes is totally impractical. Nonetheless, if you have fish that have a considerable monetary or sentimental value, and add new fish without a quarantine period, you will (eventually) cause your fish to die. I will explain the ‘why” of this, and then outline quarantine procedures that are both effective and practical.
Your fish harbor bacteria, and probably also harbor parasites. Fish are animals, and all animals (including you and me) are host to bacteria and parasites. Most are harmless, at least most of the time. For example, each human carries skin bacteria that can cause a deadly infection if they can get into the bloodstream. That is why our skin is cleaned with alcohol before an injection. The bacteria are totally harmless on our skin. In a similar manner, we all have microscopic animals that live on our skin and are parasites. They do us no harm, but they are there.
Often the reason fish and we are not harmed by the presence of bacteria and parasites is that our immune systems keep the organisms in check. In fact, one of the most common sources of infections that cause illness or death is exposure to new bacteria or parasites that our immune systems have not yet learned to cope with. This is why we have all heard of someone putting a new perfectly healthy fish in a tank, and several days or weeks later having other fish start to die. The new fish was carrying bacteria or parasites, or both, to which it had some degree of immunity, while the fish all ready in the tank did not have immunity to those organisms. Of course, the reverse is true as well, and is the most common reason that new, healthy fish introduced into an existing tank will often become sick and eventually die.
The purposes of quarantine are:
- to allow time for any harmful bacteria or parasites (hereafter called “pathogens”) to cause the new fish to become ill or die. (If the new fish dies, so will the bacteria and parasites.)
- to allow time for the immune systems of the new fish to adjust to any new pathogens in the owners other tanks
- to determine if the new fish is carrying pathogens that will be harmful to the owners existing fish.
When a new fish or fishes are bought, they should first be put into a tank in a separate room from existing tanks and, if feasible, on a separate floor. They need to have their own bucket, nets, hoses, etc. and not share those items with the other tanks. My first step is to just leave the fish alone, make certain they are eating well, and observe for about two weeks.
At water temperatures of 80F and up, parasites and bacteria multiply very fast. If the new fish do not die or become severely weak in two weeks, any bacteria or parasites are not harmful to it. Next, I start adding water from my existing tanks in place of water taken from the new fish. This water, of course, contains a sample of all the bacteria and parasites in my other tanks.
I totally change the water in the tank with the new fish in no more than 3 days time, and then continue to add new amounts for the next three to four weeks. If the new fish continue to be healthy at the end of that time, I know that there is nothing in my tanks that will harm them.
I then take fish from my existing tanks to put in with the new fish. I use guppies that I keep for this purpose, as well as angels with deformities. I first stress the fish by putting them in a bucket with very little water for at least 4-6 hours. Then I put them into the tank with no further acclimation. (The purpose of introducing stress is that the immune systems do not work as well when animals are under stress.) I then watch the new fish carefully for another 3-4 weeks. If they do not weaken or die, I then know that nothing about the new fish will harm the fish in my other tanks, and the quarantine period is over.
In the examples I have given, none of the fish became sick. If the fish become sick, the aquarist must decide whether to medicate or destroy both the ill fish and the new fish (if different). If the aquarist chooses to medicate, and the fish recover, the quarantine period must start again! The reason is because the fish might have become ill due to only one of a number of pathogens that are being harbored, and each pathogen needs to be identified.
Personally, I destroy the ill fish, wash out the tank(s), buckets, airlines, nets, etc. with a Clorox solution, and decide whether to start over with new fish. The reason I do not medicate is that almost none of the medications are effective in water with a pH above 7.5, and my pH is 8.0. While I can treat for external parasites with medications that is not pH sensitive, such medications are not effective for internal parasites. With my limited choices, I would rather destroy the fish than take a chance of a pathogen entering my hatchery.
I hope I have convinced you to quarantine all new fish and offered advice that you will find useful in doing so.
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