Without question, one of the most important things you can do for your pet fish is to isolate new fish for at least 2 weeks (4 to 6 weeks is ideal) before introducing them into your aquarium.
The term “quarantine” derives from the old practice of isolating new arrivals (humans and cargo) for 40 days in order to reduce the spread of harmful diseases. When we use this word today it generally refers to the isolation of animals for a set period of time in order to control contagious diseases. While slightly inconvenient, this valuable practice can save you time, money and heartache in the long run.
What You Need For Quarantine
A 10-gallon aquarium equipped with an inexpensive box or sponge filter powered by an air pump is all that’s needed for most quarantine setups (the simpler the better when it comes to quarantine). A small heater and aquarium hood may also be helpful. You should keep a log book and record dates, behavior, feeding and general appearance as they apply to your new fish.
Once fish have been introduced to a quarantine tank, no new fish should be added until the quarantine period is complete. After healthy fish have been placed in your primary aquarium, the quarantine setup can be cleaned and prepared for use again (all filter material should be discarded and the permanent components rinsed with hot water and left to dry for several days).
What Does Quarantine Do?
Quarantine is a good thing for your pet fish. Many people don’t realize that a fish in a pet store may have been exposed to dozens or even hundreds of fish that have recently been shipped from different points around the world. And one of the most stressful times in a fish’s life is during and immediately following shipment (your fish might have spent days or even weeks in transit), lowering the immune response. In many cases, these fish share the same food, water, nets and filters. Because bacteria, viruses, fungi and parasites move efficiently through the water from one fish to another, transmission is almost certain within any given tank.
Whenever you add new fish to your aquarium, they should be isolated and closely observed for about one month for any signs of disease or distress. While most people would like to introduce their new pets to the aquarium immediately, a little patience can go a long way in avoiding trouble. Most contagious fish diseases will become evident within one month of purchasing a new fish. Chances are, if a fish doesn’t come down with a disease within several weeks of shipment, it’s probably in good health.