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Hospital Tank Without Filter ( Is It Possible? )

A hospital tank without filter is something that concerns many aquarists. Can you do it? What are the pros and cons?

Hospital tanks are small, typically 10 or 20 gallons, aquariums used to house sick or injured fish. Hospital tanks are often set up without a filter to ensure the water quality is as stable as possible and to prevent further stress on the fish.

While it is possible to set up a hospital tank without a filter, there are several drawbacks that you should be aware of. This article will resolve any questions you have about setting up a hospital tank without a filter.

hospital tank without a filter

Should A Quarantine Tank Have A Filter?

A quarantine tank or a hospital tank is usually used for new fish to prevent the spread of disease to your established aquarium. It is also where you can treat sick fish without risking infecting the rest of your fish population.

You can set up a quarantine tank with or without a filter. There are pros and cons to both approaches, and the decision of whether or not to use a filter should be based on your individual situation.

If you decide to set up your quarantine tank without a filter, there are a few things you need to keep in mind.

  1. You will need frequent water changes to ensure the water quality stays high.
  2. You must be careful about what you put in the tank. You should sterilize any decorations or substrates before being added to the tank.
  3. You will need to watch the fish closely for any signs of stress or disease. Without a filter, it will be easier for diseases to spread, so you need to be extra vigilant.

Advantages of a Hospital Tank Without a Filter

There are several benefits to installing a hospital tank without a filter.

The water quality will be more stable without the filter constantly churning up the water. This can be beneficial for sick fish that are already stressed out.

If you use a filter, the medications used to treat your fish can be removed by the filter media. If you don’t use a filter, the medicines will stay in the water longer and be more effective.

Disadvantages of a Hospital Tank Without a Filter

Can a Paludarium Survive Without a ...
Can a Paludarium Survive Without a Filter?

There are various drawbacks to installing a hospital tank without a filter.

  1. The most significant disadvantage is that you will need more frequent water changes to maintain water quality. This can be time-consuming and challenging, especially if you are already dealing with a sick fish.
  2. Another drawback is that it can be more challenging to monitor the water quality without a filter. This is because the filter can act as a mechanical filter, trapping particles in the water that can give you an indication of water quality.
  3. Further, if you use the hospital tank for new fish, they may be stressed without the beneficial bacteria found in a filter. This can lead to disease and death.
  4. Finally, without a filter, there is a greater risk that diseases will spread. This is because the water quality can deteriorate more quickly than with a filter.

What Fish Can We Keep In A Hospital Tank Without A Filter?

If you use the hospital tank to house sick fish, you should always choose the filterless option. If you intend to use it in new fish, only some species of fish can survive and thrive in a hospital tank without a filter.

Some of the best fish for a filterless hospital tank include:

  • Bettas
  • Guppies
  • Platies
  • Swordtails
  • Mollies
  • Danios
  • Barbs
  • Corydoras
  • Loaches
  • Gouramis

Some of the worst fish for a filterless hospital tank include:

  • Discus
  • Angels
  • Rasboras
  • Tetras

The decision of whether or not to use a filter in your hospital tank should be based on your individual situation. If unsure, it is always best to err on the side of caution and use a filter.

hospital tank without a filter

How Long Can Fish Survive Without A Filter?

As we mentioned above, there are fish that can survive without a filter and fish that cannot. Some fish usually have a longer lifespan in a tank without a filter.

This is because these fish are more tolerant of poor water quality. They can also withstand more stress and are less likely to succumb to the disease.

Those who do not have a long lifespan in a tank without a filter are usually more sensitive to poor water quality and stress. They are also more likely to contract diseases.

These fish usually survive in a filter-less hospital tank for about 3 to 7 days. After that, they will need to be moved to a tank with a filter. If kept longer, they will likely die.

What Does A Filter Do?

A filter is a device that is used to remove impurities from water. The most common type of filter is a mechanical filter. This type of filter traps particles in the water, such as dirt, debris, and algae.

You can use a mechanical filter in both fresh and saltwater tanks. In a freshwater tank, a mechanical filter will also remove dissolved toxins from the water.

The second type of filter is a chemical filter. This type of filter uses chemicals to remove impurities from the water. The most common type of chemical filter is an activated carbon filter.

An activated carbon filter will remove dissolved toxins from the water, such as ammonia and nitrites. It will also remove medications that have been used to treat sick fish.

The third type of filter is a biological filter. This type of filter uses beneficial bacteria to remove impurities from the water. A nitrifying bacteria filter is the most prevalent type of biological filter.

A nitrifying bacteria filter will remove ammonia and nitrites from the water. It will also remove dissolved organic waste, such as fish waste and uneaten food.

However, if used in a hospital tank, the medications used to treat the sick fish will destroy the beneficial bacteria in the filter.

So, as you see, filters basically remove impurities from water to keep the tank clean. As fish require clean water to thrive (and even to survive), a filter is an absolute must in any fish tank.

Hence, keeping a hospital tank without a filter is a risk we take if we have no other choice.

How Can We Keep The Hospital Tank Clean Without A Filter?

Fortunately, there are things we can do to keep our hospital tank clean and suitable for our fish. However, it will take much of your time and effort. These things include;

Perform water changes every day

The essential thing you should do is replace the water every day. This will remove the impurities that have accumulated in the water.

You will need to remove about 50% of the water in the tank and replace it with fresh, clean water. You can set up a schedule to make the water changes more manageable.

For example, you can remove 25% of the water on Monday, Wednesday, and Friday. Then, you can remove 50% of the water on Tuesday, Thursday, and Saturday. Finally, you can remove 75% of the water on Sunday.

By following this schedule, you will be able to remove the impurities in the water without having to work hard as you expect.

Use an air pump

Using an air pump is another way to keep your hospital tank clean. The air pump will provide the tank with oxygen.

Oxygen is necessary for the fish to survive. It will also help to keep the water clean and free of impurities.

An air pump can be used to aerate the tank’s water. This will help remove the impurities in the water and make it easier for the fish to breathe.

Further, you can use an air pump to circulate the water in the tank. This will help to keep the water oxygenated and clean.

Use a sponge filter.

While our hospital tank doesn’t have a filter, we can still use a sponge filter. Sponge filters are ideal for tanks without filters since they are simple to install and very effective at removing pollutants.

A sponge filter will remove small particles, such as dirt and debris, from the water. It can also remove dissolved toxins, such as ammonia and nitrites if it already has colonies of beneficial bacteria.

However, if you use medications in your hospital tank, the sponge filter will not remove them from the water.

In this case, you may have to clean the filter daily to remove the debris and toxins.

hospital tank without a filter

How Often Should I Change Water In A Filterless Tank?

As we’ve seen, water changes are very important in a hospital tank without a filter. But how often should you change the tank water?

Ideally, you should change the water every day. However, if you can’t do that, you should change the water at least three times a week.

By changing the water regularly, you will remove the accumulated impurities in the water. This will make the water cleaner and healthier for the fish.

Tips To Maintain The Hospital Tank Without a Filter

If you choose to prepare a filterless hospital tank, there are things you can do to maintain it as healthy as your display tank. Although some of them are mentioned above, we will list all of them here.

  • Change the water regularly: as we’ve seen, water changes are very important in a filterless tank. You should change the tank water every day, if possible. If you can’t do that, you should change the water at least three times a week.
  • Use an air pump: an air pump will help keep the water oxygenated and clean. It will also help to remove the impurities in the water.
  • Use a sponge filter: a sponge filter will remove small particles, such as dirt and debris, from the water. It can also remove dissolved toxins, such as ammonia and nitrites.
  • Don’t overstock the tank: When setting up the hospital tank, don’t add too many fish. The fewer fish you have in the tank, the easier it will be to keep the water clean and healthy.
  • Avoid filters and other equipment with active carbon: Using activated carbon in the hospital tank will remove the medications you add to the water. This can be detrimental to the fish’s health.
  • Avoid adding substrate: As we do not have a filter in our tank, we should be able to easily remove dirt from our tank. Substrates like gravel make removing dirt and debris from the tank more difficult.
  • Don’t use decorations: decorations can be a breeding ground for bacteria and parasites. Decorations can also make it more difficult to clean the tank.
  • Use a small hospital tank: a small tank is easier to maintain than a large one. It is also easier to keep the water clean and healthy.
  • Use live plants: live plants can help keep the water clean and healthy. Plants will also provide oxygen for the fish.

Final Words

A hospital tank without a filter is ideal if you use it to treat your sick fish. However, if you use the hospital tank for new fish that show no disease symptoms, it is better to use a filtered hospital tank.

This is because they are already acclimated to filtered tanks and may get weakened if placed in a new environment.

However, keeping them quarantined is essential as new fish may be carriers of diseases and parasites that can infect the other fish in the main tank.

If you have a hospital tank without a filter, change the water regularly and use an air pump to keep the water oxygenated.

Don’t overstock the tank, and avoid using substrate and decorations. Following the above tips, you can maintain the hospital tank without a filter and provide a safe and healthy environment for your fish.

Credit to : Michael’s Fish Room
Read Next : Ways To Clean Aquarium Filter Without Killing Bacteria

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About Dr.Chamika

Hello, I'm Dr. Chamika. I am a Researcher in Water quality, Aquatic organisms, and Environmental chemistry. I am a passionate fish keeper, with10 years of experience. My mission is to help other aquarists experience the joy of fish keeping.