Hello Pam,

Here's a link that should help you. Personally, I've kept an aquarium off and on for 34 years and never used a hospital tank. If I noticed a fish with a problem, I treated the whole tank to cure it and prevent it from spreading to my other fish. Have a good one. Jimmy

Here is a link that might be useful: quarantine tank

I didn't have one when I was at home, but when I went to work for a tropical fish wholesaler I did so. I just set a small tank with a filter and heater and used it for meds. I think it's a good idea to have it running alll the time, so that it can go through the Nitrogen Cycle.

Some meds actually kill the bacteria in the filter so cycling is not always necessary. You could always run 2 filters in your existing tank. But htis is one reason to have the extra tank, so you aren't treating well fish unecessarily or risk crashing your established system.Use the extra filter when a hospital tank is needed. New fish should be QT'ed in a hospital tank / QT tank for a few weeks before adding the fish to your aquarium. The longer the better. 3 months would be ideal. Aother option is to fishless cycle the Qt/hospital tank with household ammonia, and always dose the tank with ammonia daily until needed.But that would be a PITA wouldn't it. Or have 2 QT tanks with maybe a few guppies or platy's, well understocked. Then when the use is needed simply transfer fish from one tank to the other. There are other ways if you get creative.