How To Setup an Easy Quarantine Tank

How To Setup an Easy Quarantine Tank

Anyone familiar with the fish and shrimp keeping hobby would know that it is important to quarantine new additions before introduction to the main tanks.

The purpose of this practice is to mitigate disease outbreaks i.e. to minimize the risk of new fish or shrimp transferring disease-causing organisms and parasites to the already established stock in your tank.

Apart from the basis of quarantining new stock before adding them into your tank, one may be required to move sick or possibly sick pet from the main tank to a quarantine tank where it will be treated and nursed back to good health in the case of sickness or injury.

If we introduce disease into one of the tanks, it could very rapidly spread to other tanks. So we want to reduce that risk as much as possible.

Do not take it lightly! One sick animal can actually wipe out an entire tank! This is why lots of aquarists are so adamant about quarantine their fish.

In this article, I will be talking about how to establish a quick and easy quarantine tank for your aquarium fish, in addition to all the essential equipment needed for the set up.

Even though I will be using the term ‘fish’ throughout the article, let it not confuse you. Everything can be applied to dwarf shrimp, freshwater snails, crabs, crayfish, frogs, etc. as well.

For more information, read the article “Understanding Dwarf Shrimp Diseases and Parasites”.

Why it’s Important to Treat Fish in a Quarantine Tank

Quarantine is the force isolation of fish in order to prevent the transmission of illness or disease.

One of the essences of treating sick fish in a separate quarantine tank is to prevent the contact of medications with healthy ones.

Since healthy animals do not need these medications; subjecting them to it might be risky, as they could be stressed out as a result of its potency.

The sick fish are meant to be separated/isolated from the rest of the stock, and preferably moved to a quarantine/hospital tank for due treatment.

Additionally, it’s clearly more economical and easier to treat infected pets in a smaller body of water than in the main tank. Fish medications are not that cheap, so treating your diseased fish in a small quarantine tank will help save a lot of money.

Other Benefits of a Quarantine Tank

Stress management: The quarantine tank allows your aquarium fish to relieve themselves of the stress they endured during packing, transit, and unpacking.

It serves as a temporary home for the new animal, giving it adequate time to recover before being moved into a new tank with new tankmates. In summary, quarantining makes it easier for them to cope with life in the main display tank.

Observation: Through observation of the newly purchased animal, one can be able to monitor and ascertain the health of the aquarium fish by watching its body movements and reactions.

It is easier to observe fish in a small quarantine tank, that way, you can quickly tell if the fish is showing symptoms of an illness or injury.

Controlled feeding: Some species of fish can be difficult to acclimate to prepared foods, thus they may reject various food items.

Keeping such fish in a quarantine tank will help the fish adjust, endeavor to give it the proper care and with time the fish will become ready to accept new types of food.

If you are quarantining newly purchased fish, it’s best to keep it in the tank for 4-6 weeks before moving it to the main tank.

This will allow you to observe your aquarium fish closely and extensively for any sign of parasites or disease condition. Peradventure you notice any disease symptom during this period, commence medication immediately and wait for a few weeks to monitor improvements.

Note that, you can only relocate the fish when it has fully recovered, or else you are at risk of introducing pathogens and parasites into your display tank.

Quarantine Tank and Excuses

People often do not quarantine their animals because they do not have enough patience. We saw some beautiful fish in stores and we want to put them in our main tank right now!

In addition, frankly saying, people are very lazy. It is really hard to accept that but we always find lots of excuses like:

  • I don’t have a separate tank for that,
  • There is no place for another tank,
  • It was a reputable seller, etc.

Well, quarantine is a must and all these excuses are unfounded at best, and normally totally incorrect.

  • We do not have to use anything fancy for that.
  • There is always room for a small container.
  • Don’t care where it comes from. You should not jeopardize the main tank.

Equipment Needed for A Quarantine Tank

To set up a quick and easy quarantine/hospital tank for your aquarium fish, you would need the following things:

  • A quarantine tank or tub.
  • Filter: A sponge filter would do the job; this provides gentle mechanical and biological filtration in the tank.
  • Heater (if needed).
  • Basic decors: To provide hiding places for the fish.

How to Set up a Quarantine Tank

With some exceptions, the process of setting up a quarantine tank is almost the same as any other freshwater tank. However, because it a smaller and simpler version of the common tank, we can make a quick and easy quarantine tank.

Step 1: Choosing a Container for the Quarantine Tank

As I have already said earlier, we do not have to spend loads of money on a fish tank and a stand and all of these different things. It doesn’t need to be anything special.

So, a quarantine tank can be small like a 10-gallon (40L) tank, or if you’re keeping smaller fish even a 5 gallon (20 l) will do well enough.

So, what can we use for the quarantine tank:

  • a small glass tank,
  • a plastic tub, or a storage container.
  • a plastic bucket (if you do not have anything else). Just make sure that this is a clean bucket that’s never been used with any kind of chemicals. DO NOT use a bucket made out of zinc, aluminum, or copper. Water will come into reaction with these elements causing an imbalance. It must be a special bucket for the aquarium or made out of plastic at least.

Empty shrimp tankA glass tank is actually better as it allows you to have a clearer view of the inside whereas a plastic tub is cheaper.

However, an advantage of using the plastic tub is that you will not be tempted to graduate it into another display tank and deprive yourself of an available quarantine tank for next time.

Important: When animals are stressed out, they may jump or crawl out of the tank. So, you will definitely need a cover on that tank.

Ensure to get a tight-fitting lid to stop the fish from jumping out of the tank and also to prevent evaporation of water.

Make holes in the lid to allow for proper air flow— exchange of gases, these holes will also help to pass through the airline tubing.

Step 2: Cleaning and Testing Quarantine Tank

shrimp tank Hydrogen PeroxideRinse the tub/tank well with clean water. If you have time, you can allow the water to sit for 24 hours to make sure the tank is not leaking.

Place the quarantine tank/tub on a flat surface, for example: a counter top, table, or floor in a quiet room.

Cleaning is a very simple process. Do not use soap. You need something that will decompose and will not leave any trace in the tank.

For example, we can use Hydrogen peroxide (H2O2). This is a cheap and handy household supply that is often used for cleaning and disinfecting. Spray it on the walls, and let it sit for 10 – 20 minutes. Next, wash it off properly.

Note: Use gloves for safety.

Hydrogen peroxide – check out the price on Amazon

Step 3: Filling up the Quarantine Tank

Now you can fill the quarantine tank with conditioned water.

Note: Some people use conditioned water and water from the main display tank in the ratio 50:50. Personally, I do not see any reason for that.

Do not forget to age water prior to use (24 hours). By letting it stand, we also remove chlorine. Chlorine will usually evaporate out of water within 24 hours.

Keep in mind that “aging” does not remove chloramines. To remove them we need to use water conditioners (like Seachem Prime).

When it is done, it is time to place the filter in the tank.

Step 4: Install Your Filter (Filer Media from the Main Tank)

All aquariums need filtration – and the quarantine tank is no different. The filter performs 2 main tasks:

  1. Cleans up floating debris.
  2. Harbors beneficial bacteria that allow the tank to cycle and become a healthy eco-system. Otherwise, you are going to have an ammonia spike and end up killing those fish instead of saving them.

There are several most popular types of aquarium filters out there (Canister filters, hang on the back filters, and sponge filters). Each of them has its own pros and cons.

Read more about it in my article “The Best Filtration System for Breeding Shrimp”.

Canister filter is the best choice for water quality, however, in my opinion, the sponge filter is ideal for the small quarantine tanks (up to 10 gallons or 40 L).

Nonetheless, we cannot use a new filter (not cycled) in our quarantine tank because we do not have time for that. We are talking about emergency situations. At the same time, any quarantine tank needs to be cycled.

So, what can we do?

How To Setup an Easy Quarantine Tank filter air pumb air tubesWe can take the filter media out of their existing tanks and use it in the quarantine tank. This filter already contains beneficial bacteria and it should be enough for the small tank.

Therefore, whenever it is possible, install and keep the second filter in the main tank in advance. Generally, it can take up to 2 weeks for bacterial colonization.

It will give you a nice cycled filter ready for you any time you might need it then if anything ever happens. Consider it as your safety net in cases something goes wrong.

Some examples (links to Amazon):

Note: Keep in mind that a cycled filter still does not guarantee that you will not get the problem in the form of a mini-cycle. Mini-cycle is the result of an insufficient amount of beneficial bacteria compared to the existing bioload in the tank.

IMPORTANT: Never use the second filter back and forth between your quarantine tank and your main tank without proper cleaning! This is a ‘great’ way to contaminate the main tank as well.

After treatment, if you decide to put the second filter back into the main tank, make ensure that that sponge filter is cleaned out.

It means:

  • bleaching it,
  • letting it dry out and,
  • washing it over and over again.

I do not have the Second Filter!

A lot of people do not have multiple tanks in their homes and they often do not keep the second filter. If you are one of them, I would recommend buying and keep a bottle of beneficial bacteria.

There are many really good products on the market, for example (links to Amazon):

How To Setup an Easy Quarantine Tank beneficial bacteria

They are all one of the most reliable bacteria starters you can find when we are talking about the natural removal of ammonia, nitrites, and prevention of the new tank syndrome.

Note: DO NOT forget to turn off or unplug UV sterilizers prior to each introduction of beneficial bacteria. 

I do not have the Second Filter and the Bottle of Beneficial Bacteria!

Well, in this case, there is no much you can do, except doing frequent and large water changes to prevent ammonia spikes.

In our hobby, we should always think in advance. We must be ready for emergency situations (like quarantine). Therefore, we must have products that we might never use.

Step 5: Adding Decorations

Add the decors (caves, rockworks, stones, etc.) and artificial plants to the quarantine tank, these provide comfortable places where the fish can hide whenever it wants, thus reducing stress.

I need to stress it out – We do not add decorations to the tank to make it nice and beautiful! That is why live plants are not recommended, especially if you are going to dose aquarium salt which might cause them to rot.

Use PVC pipes, artificial plants, rocks, etc.

Be careful with driftwood, because of its organic nature, it can also harbor pathogens. So, if you are not sure about it, do not add it.

Read more in the article “Driftwood in Shrimp Tank”.

Substrate, Lighting, and Heater

Bare Bottom:

The quarantine tank needs to be left bare, with no addition of sand or gravel substrate to the bottom. This will help prevent leftover food and other waste from collecting at the bottom of your quarantine tank, thus making the maintenance of water quality a whole lot easier.

The PROS of bare bottom quarantine tank:

  1. The simplicity of maintenance. It is very easy to clean. You can take siphon and eliminate all the waste very quickly. Nothing gets under the substrate.
  2. Easier to maintain water chemistry at a certain level. The substrate can increase or decrease water chemistry in a tank.
  3. No parasites and unexpected guests can be in the substrate and live there.
  4. It does not cost you anything!


Also, lighting is not needed. We do not have plants that require lighting and this is not a display tank. In addition, it might stress the sick fish. Light through the window is enough for the quarantine tank.


Unlike humans, our aquatic pets (fish, shrimp, crabs, snails, etc.) do not produce their own body heat. They have to rely on the temperature of the water to maintain their body temperature.

Therefore, it is absolutely crucial that you keep your aquarium at the proper temperature for your pets.

The inadequate temperature will only increase the stress level of the fish making them even weaker and more susceptible to the diseases.

That is why, whether or not you need the heater depends on the species you have in the quarantine tank because you have to adjust the temperature accordingly.

Tip: If you are using the plastic tub – DO NOT lay the heater directly on the plastic! It is important to point out here that not all plastics are fish safe. It can lead to melting the tub.

In addition, get an accurate thermometer to monitor and ensure that the temperature is optimal for your fish. When that has been ascertained, then you can proceed to acclimate the fish.

Example of the heater for the small tank – Hygger Mini Inline Quartz (link to check the price on Amazon).

How Long Should We Quarantine the Fish

How long am I supposed to quarantine my fish? This is probably the most frequent question.

Unfortunately, nobody can tell you for sure.

The problem is that different diseases have different life cycles and different expressions of that and temperature can play a role as well.

However, it does not mean that we should do it for months as well.

In most cases, if there are going to be problems, those problems are going to arise over the course of 1 to 3 weeks and often within the first few days.

If you really want to do it right, you can wait 30 days to make sure there is no visible disease and your fish are acting, swimming, and eating properly.

Important: If at any point in those 30 days, fish develop some type of infection, you have to restart the time you treat the quarantine tank. So, that 30 days start from the time you supposedly eliminated that disease.

Trick: After a week or two, some aquarists add in the quarantine tank one or two fish from the main tank. They do that when they feel like the fish is healthy and it’s not holding any diseases. Therefore, if newly added fish do not get sick after a few days, it can be a sign that everything is OK.

Personally, I do not use this test method. However, if you want to try it – do not use your best fish!

Maintaining the Quarantine Tank

You don’t have to do much, just make sure to perform frequent water changes to prevent the build-up of ammonia (uncycled tank). No ammonia is the goal. So, you would have to do daily water changes on a tank that has not cycled.

If the tank is cycled, then you are to carry out water changes less frequently.

Tip: While doing water changes, when you drop the water level, rub the inside of the tank in

the bottom of the glass to remove any potential disease agents.

It’s advisable to use a sponge filter from the main display tank as it would have been colonized by beneficial bacteria.

The filter media will aid in preventing build up of ammonia and nitrite which will further stress an already sick fish. Be sure to test regularly for ammonia, nitrate, and nitrite in the quarantine tank in order to maintain good water quality at all times.

Also, avoid the usage of carbon and UV sterilizers in a quarantine tank as these will break down medications, thereby reducing their effectiveness.

Important: Dwarf shrimp do not like changes. It can be a problem if we have to do frequents water changes (Molting problems. The White Ring of Death). Therefore, it is highly recommended to keep them only in the cycled quarantine tank!

Clean Accessories:

Anything that is going into that quarantine tank cannot be used in any other tank!

Nets, algae scrubbers, siphons, pumps, filters, buckets, etc. – use that equipment only for your quarantine tank.

Note: When you are through with the quarantine process, do not forget to clean and disinfect the quarantine tank and decors utilized. Avoid using harsh cleaning chemicals, rather a dilute bleach solution should be used. Also, make sure to rinse the tank after disinfection with a bleach solution, and allow it to dry pending its next usage.

If you do not have a choice and have to use some accessories for other tanks, at least do not do it on the same day. Clean it and let those things dry out.

Where to Place Quarantine Tank

I would like to point out that sometimes people make this simple mistake, they put a quarantine tank right next to other tanks.

This is a bad idea!

Our hobby is pretty messy and we often spill water when we do water changes or netting. When it gets on the side of a tank, it may go into the tank.

So, ideally, you do not want to keep them together side by side.

How to Disinfect a Used Accessories or Contaminated Tank with Bleach

Bleach (link to check the price on Amazon) is a strong and effective disinfectant. It’s active ingredient – sodium hypochlorite, denatures protein in microorganisms and is therefore effective in killing bacteria, parasites, algae, fungus, and viruses.

Note: Use latex gloves when you are working with bleach!

Household bleach works fast and effectively and it is widely available for purchase at low costs.

Here are the procedures to follow:

  1. Use a regular bleach eg. Clorox at a recommended ratio of 10 cups water to 1 cup bleach (10:1). For this purpose, use bleach that contains as few additives as possible (no soap, perfume, colorant). If using concentrated bleach, use ¾ of a cup.
  2. Fill the quarantine tank with warm water.

Note: You can use a spray bottle if the tank is too big.

  1. Add the bleach solution into the water and leave it there for 15 – 30 minutes. Use a new sponge to clean the outside walls of the tank.
    Note: If you are using the spray bottle, spray it all other the tank (inside and outside). Leave it for 15 – 30 minutes.
  2. Drain the water containing the bleach solution and clean it with clean tap water.
  3. Rinse and clean it again.
  4. Use Seachem Prime (link to check the price on Amazon) or any other dechlorinator.
  5. Make sure that there are no spots left unattended.
  6. Let it dry out for a few days.

Important: It is not recommended to clean driftwood with bleach. Driftwood is porous and will absorb some bleach solution. We do not need that. If you want to reuse driftwood in the future – boil it! Read more about it here.

Bleach and Filter Media

If you had a really bad disease outbreak – I would recommend throwing the used filter media/sponge away!

However, if there were no problems in your quarantine tank but you still want to play safe – I would recommend using a lower concentration of bleach/water (1:15).

The process is the same.

In Conclusion

Keeping a quarantine/hospital tank is an integral part of the hobby, it is an insurance against microbial infections prevalent in newly purchased fish and an abode for nursing diseases as well as injuries inflicted on aquarium fish by aggressive or nippy tankmates in the display tank.

So, be sure to make provisions for a quarantine tank where you can properly monitor new fish and treat sick or infected fish.

Get a container and place the necessary equipment to make the environment conducive enough for your aquarium fish and in turn, they will thrive successfully during their brief stay till it’s time to move back into the main tank.

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