Published on 01-10-2019
We strive to keep our aquariums clean and our fish safe from any illnesses or parasites. We also take care not to let any foreign substance get inside our tanks, or it can be a health hazard for our aquatic friends. When we get a new fish for our tank, whether we get them from a store or the wild, chances are that it might be carrying some disease or parasite. And as the tank is a very small and limited space, it doesn’t take long for any infection to pass over to the other fish.
So it is always beneficial to check for any problems with the new fish before putting it in the main tank. If there are issues, they can be treated there itself, away from your older fish. The best way to do this is to set up another, usually smaller tank where you can observe the new fish for any signs of problems.I’ve written more on how to identify symptoms in a sick fish here.
This separate ‘hospital’ tank is called a quarantine tank. It is indispensable for anyone who wants their fish to lead healthy and long lives. People often don’t set up a quarantine tank because they think it will add a lot to their costs. However, as we will see later in this article, these tanks only need minimal equipment and are fairly cheap to set up and run.
The uses of quarantine tanks:
- Check and treat new fish for illnesses / parasites
A quarantine tank can be used to keep new fish for a few days, separated from your other, healthy fish. Sickness in the new fish can be checked and treated here, before they are added to the destination tank. This way you can rest assured that diseases / parasites won’t spread in your main tank.
2. Acclimatise fish for transferring to other tanks
If you have more than one tank, you may need to transfer fish from one tank to another. The water in one tank will have different properties than the other one. You can first put the fish in the quarantine tank and slowly acclimatise it, so that it used to the water conditions in your destination tank. You can do this by putting the fish along with the water from its older tank in the quarantine tank. Then, you can add a small quantity of water from the destination tank into the quarantine tank, every few minutes, so that the fish gets used to the temperature, chemical composition, etc.
When you have added enough water that about 2/3rd of the water is from your main tank, you can safely take the fish out in a net and put it in the main tank. When you’re adding water slowly, there will be very little water in the quarantine tank in the beginning. You will need to place the aquarium heater horizontally in such a way that the entire heater (or heating element) is completely submerged underwater. If it is only partially submerged, it could crack and electrocute the fish!
3.Acclimatise new fish
New fish will come in a bag with water from the tank in the store. This water will have different parameters than the water in your tank. So the fish will need to be acclimatised to the water conditions in your tank. Since they will be quarantined in the quarantine tank anyway, you can use this time to slowly get them used to the water in your tank. The procedure to do this is the same as mentioned in the above paragraph.
4.Treatment tank
If the quarantine tank is not in use and one or more of your fish get affected by a problem that is not contagious (like swim bladder disorder or constipation), you can transfer them to the quarantine tank for treatment. Here, they will be able to rest better and you will be able to observe them better. However, if they are affected by a contagious infection, it is better to treat them in the main tank itself, as the infection may already have transferred to other fish.
5. Breeding tank
If not in use, a quarantine tank can also double up as a breeding tank for appropriately sized fish. The tank should be big enough to comfortably breed the species of fish you’re breeding. You can read more on setting up and using a breeding tank here.Fish eat baby fish without a though. So, you can transfer newly hatched babies into the quarantine tank so they can grow up in peace.
6. Isolate Fish
You may get aggressive fish that are hurting or harassing your peaceful fish. Or, some fish may suddenly start behaving in an aggressive manner for some reason. In such cases, having an extra tank really comes in handy, as you can keep them separated and in peace.
For how long should the fish be kept for quarantine?
The fish should be kept in the quarantine tank for at least 2 weeks. This much time is sufficient to notice if something is wrong. If there is some problem, you may need to keep them longer, until the issue is completely treated. After all the symptoms are gone, you could wait another week to ensure that they don’t return and your fish is good to go to its destination tank. I’ve written more on identifying symptoms and diseases here.
New Tank Syndrome and how to avoid it
Whenever fish are treated in a quarantine tank and then transferred to the main tank, the quarantine tank needs to be sterilised, to prevent future contamination. When this is done, all the bacteria in the tank will die. Now, when you transfer other fish that are sick or for any other reason, there won’t be any beneficial bacteria in the quarantine tank. This is called the New Tank Syndrome, and is an issue whenever a new tank is set up. While for brand new tanks the usual thing to do is to cycle the tank, this is not practical for quarantine tanks.
So, you need to have some extra beneficial bacteria ready at all times. You can keep some extra filter media in your main tank next to the filter, or in the sump, if you have one. Bacteria will grow and establish a colony in this filter media. You can put this filter media in the quarantine tank when you add fish to it. When you don’t need the quarantine tank anymore, be sure to sterilise the filter media along with tank too, before putting back inside the main tank.
How to sterilise the tank
First, remove all the water from the tank, but leave all the equipment inside. You can disinfect using vinegar or regular bleach. If using vinegar, add 1 or 2 cups in the quarantine tank. If using bleach. Use about 2 tablespoons worth per gallon of water. Add fresh, clean water to the tank until it is full. All the equipment and filter media should be submerged in the water. Leave it for 24 hours.
Next, you can take each piece of equipment individually and scrub them with a brush. Also scrub the inside and outside walls of the tank. You can use the vinegar / bleach water for this. Next, rinse all the equipment and the tank with clean water. Leave to dry until completely dried through. The filter media could take a few days to dry completely.
Note: Only sterilise the filter media if you’re using something like a corner filter or something. If you’re using a sponge filter, it is best to throw the media away and replace it with new media the next time.
What you will need to set up a quarantine tank:
- The tank itself
A good size for a quarantine tank is about 2x 1.5x 1.5 ft. / 24x 18×18 in. / 61 x 45 x 45 cms. A tank of this size is small and light enough to be portable, and can keep fish up to 6 in. / 15 cms. It could be made either from glass or acrylic. A tight fitting hood is necessary, along with Styrofoam or Thermocol to keep under the tank.
Remember, a fish under quarantine will be stressed out for most of its time there, so it will probably jump. The tank should be placed away from bright lights and places where temperature fluctuates a lot, like the kitchen or in front of a window. A relatively dark corner of the room is just fine. Unlike a regular aquarium, a quarantine tank does not need artificial lighting or substrate of any kind.
- Sponge filter
A sponge filter is the best filter for a quarantine tank because it doesn’t make the water flow. This keeps the water relatively still, which is good for sick fish as they won’t have to spend extra energy just to swim. They can relax and recover in peace. The sponge filter also releases air bubbles into the tank. So you don’t have to keep an air stone just for that purpose, which means less equipment in the tank, which means more space for the fish to move around.
Chemical filtration can filter out the medication from the water, making it ineffective. Sponge filters don’t do chemical filtration, so the medication will be able to work effectively.
- Heater
Keeping the temperature of the water at a higher range will help in getting rid of parasites faster. To find out what temperature range your fish species can tolerate, along with the other water parameters, please click here. The heater should have a built in thermostat, so it can regulate the temperature effectively.
Heaters without thermostats should never be bought, as they will keep on heating the water, effectively boiling the fish alive! For even heating, you can place the heater diagonally on the tank’s wall.
- Hiding spots
As the fish under quarantine will be stressed out, they will need places to hide out of sight and feel comfortable and safe. You could use PVC pipes, earthen pots, small pieces of driftwood or decorations that are rated aquarium safe, as these won’t leak harmful chemicals into the water.
- Thermometer
To ensure that the heater is working properly and the temperature of the water is what you want it to be, you will require a thermometer. Ones with digital screens and a probe that goes into the water are quite cheap and will tell you the temperature reading at a glance.
- Plastic plants
Some species of fish need plant cover to feel safe. If you have such species, you can get aquarium-safe plastic plants that have weighted bases, so you can keep them even without a substrate. You can read short bios of various fish species over hereto find out what the ideal conditions for them are.
- No substrate
While this point was mentioned in point 1, it is necessary to understand that some parasites require substrate at some stages in their life cycle, and not giving them this will interrupt their reproduction. Also, if some parasites fall to the ground, you will be able to spot them easily. As it is not always immediately apparent which parasites you are dealing with, a bare bottom tank can help you spot them and then you can use the appropriate medication.I’ve written more on how to spot and treat fish diseases here.
- Water testing kit
This is a no brainer. A water testing kit is needed to monitor the water parameters in any aquarium, even more so in a quarantine tank. You need to monitor the water parameters to ensure they are perfect for your species of fish, so they can get cured faster.