Quarantine tank

A quarantine tank is a separate, usually smaller aquarium set up to hold new fish, shrimp or sometimes plants for a period of observation before they join an established main tank. The goal is to catch signs of disease or parasites early, in a tank where treatment will not affect other established or sensitive livestock, and to avoid introducing something that could disrupt a tank that took months or years to establish.

A typical quarantine period runs anywhere from two to four weeks, during which the new arrivals are watched closely for changes in appetite, color, breathing or visible spots and lesions. The quarantine tank itself needs its own cycled filter, or a filter seeded with established media, since running an uncycled tank for even a few weeks can create the same ammonia and nitrite problems as a brand new aquarium. Keeping quarantine equipment separate from main tank tools, including nets and buckets, reduces the chance of carrying a problem over between tanks.

Plants can also carry snails, algae spores or pest insects, so some aquarists rinse new plants thoroughly or quarantine them separately before adding them to a planted display. A common mistake is skipping quarantine for fish that look healthy in the store, since many diseases and parasites are not visible until stress from shipping and a new environment lets symptoms appear days or weeks later.