After all the work you’ve gone to to create that special environment inside your tank, don’t muss it up by adding a sick fish. Here’s the rub: all new fish are potentially sick fish. Even if they look great at the pet store.
Enter the quarantine tank. This is a small tank kept in addition to your large show tank. You put all new fish in there for a week to a month (some fish people really do a month) to make sure they’re healthy before you add them into your community tank with all your healthy fish.
Quarantine tanks are also helpful for fish that become sick in your community tank. At the first sign of trouble, you take the sick fish out of your display tank and put it in the quarantine tank and treat it there.
Quarantine tanks have the usual components of other fish tanks – a heater, filter, and a backup thermometer to make sure the temperature is right. Sick tanks are kept a bit warmer than normal, as this helps the fish recover faster.
I’ve kept a lot of fish over the years, and only had a quarantine tank when I had my huge planted discus tank. Frankly, I am a bit too lazy to do the full and proper screening of new fish that quarantine tanks represent. However, there is a real risk to not having one. If you do get a sick fish in your primary tank, you are then basically dealing with not one sick fish, but an entire thankful of sick fish. If you picked up a really nasty illness or infection, there is a real chance most of your fish could die.
If you have a planted tank – live plants that you may love, that you bought expensive lights for, and lovingly tend to – the consequences are even worse. Many of the medications for even common fish diseases are not plant friendly. Neither are they filter friendly – antibiotics kill bacteria. All bacteria. If you have to use a strong dose, you may end up having to recycle your filter again, or at least build it up again from 10% of its previous capacity. It can be a real pain. (Remember why I like the no-tech single betta in a glass bowl?)
All that said, I have successfully treated ich and hole-in-the-head in a planted tank. You can still treat diseased, even in big fancy planted tanks. Its just a wee bit riskier. Still, if you take the time to really inspect your fish every day, you’ll probably catch an illness before its out of control. And that can make all the difference.
