Some fish hobbyists call it a quarantine tank, while others call it a hospital tank. Whatever you call these simple setup fish tanks, they have very special purposes – to quarantine new or sick fish.
Why do I need a quarantine tank?
1. To Quarantine New Fish Before Introducing them to your Other Fish in the main aquarium
There are hundreds if not thousands contagious fish diseases and parasites out there. e.g., Ick, fluke, mouth rot, etc. just to name a few. We are not trying to scare you if you are new to the hobby. It is very rare any fish disease or parasite can affect a human, but the danger is very real to your existing healthy fish.
Whenever you buy one or more new fish, you might introduce some unwanted diseases or parasites into your well established aquariums. All it takes is one sick fish to affect the whole system. Although some fish might look healthy when you just bought them, the symptoms of the diseases or parasites might not show up until after they are introduced into your aquarium. By then, it would be too late. You might end up with a tank full of sick fish or even worse just because of this one disease/parasite-carrying fish you added. Risking a loss of all your beautiful fish each time you add something new is not worth it. It doesn’t mean you can’t add new fish to your existing fish tanks. This is when you need a quarantine tank.
As experienced fish hobbyists, we recommend that all new fish to be quarantined in a separate fish tank for no less than 2~3 weeks. Most fish diseases and parasites should show symptoms on the fish within this period. To be safer, you may quarantine the new fish longer as you wish. If the new fish show no symptom of any kind for over a month, you may safely introduce the fish to your main/show tank. If the fish show any disease or parasites, you can treat it accordingly in the quarantine tank without affecting your fish in the main aquarium.
2. To Treat the Sick Fish before returning them to the main aquarium
Sometimes healthy fish can still get sick even when you have not introduced anything new for a while. It can be the result from an injury or an infection. Sometimes an infection can be contagious. You want to separate any sick fish from your healthy fish as soon as possible. This is what a quarantine tank for. Now acting as a little hospital tank for the sick fish.
There are many fish medications out there for most of these problems. However, many medications have side effects, and some of them are not only hard on the fish, but they might also even crash the aquarium nitrogen cycle by killing the beneficial bacteria in the aquarium filter system. You need to relocate the sick fish into their own tanks if you do not wish to treat the whole tank of healthy fish for just one sick fish or risk crashing the nitrogen cycle.
It is also more economical to treat sick fish in a smaller tank. For example, you can achieve the same concentration of medication in a 5-gallon tank with only half the dosage as opposed to a 10-gallon tank.
How to set up a quarantine tank?
Unlike a main aquarium for showing off, you will only need a few basic equipment for a quarantine tank setup.
1. A fish tank
2. An aquarium filter
3. An aquarium heater
4. A thermometer
5. A separated set of fish net
6. An aquarium vacuum
7. A water bucket
A quarantine tank does not require any gravel or decoration, but it won’t hurt if you have some extra to spare. Fish might feel less stressed in a fish tank with some decorations than in an empty tank.
As a quarantine tank, it should be smaller than your main tank. A 10-gallon tank should work fine unless you have large fish. A 5-gallon tank is perfect if you only keep small fish of less than 3” long.
Just like any aquarium, a quarantine tank requires a cycled aquarium filter system. You can solve this easily by having a small sponge filter running in your main tank which can be relocated into a quarantine tank when needed. You may also keep the quarantine tank running by keeping a few healthy fish in there and relocate them into the main tank to make room for the new fish when the time comes.
Important: You should have a separate set of fish net, an aquarium vacuum, and a water bucket for the quarantine tank, because these media can also transmit fish diseases and parasites if they are shared by different tanks. Likewise, you should wash your hands every time after you have worked on the quarantine tank when there is new or sick fish in there.
By having a quarantine/hospital tank, you keep your existing fish safe from unwanted parasites and diseases. It saves you the trouble and money in a long run. A basic 5 to 10 gallon quarantine tank setup can be had for under $50. This might seem to be a lot if you only have a 5 to 10 gallon main aquarium, but for those who have one large or multiple aquariums and get new fish fairly often, it is absolutely worth the cost. Some expensive fish can have the price tag of more than $50 each. This is especially true for saltwater aquariums. Therefore, it is more important for saltwater aquarium hobbyists to have a quarantine tank.