Do Guppies Need a Filter?

The main purpose of a filter in an aquarium is to clean the tank by removing food leftovers, fish waste, decaying organic matter, and harmful chemicals. A filter also helps aerate the water. The oxygen level increases when the water moves in and out of the filter. So, do guppies need a filter?

Guppies need a filter since they produce wastes that need to be filtered from the water, or they’ll fall sick and may die. A filter also aerates and circulates the water, keeping it fresh. When the guppy waste and food leftovers decompose, they will cause ammonia poisoning, which will kill the fish.

Also, chlorine or other impurities may get into the tank when adding water to the tank. Since ammonia poisoning is not visible, it is important to have a filter to clean the tank.

Guppy fish

How does an aquarium filter work?

A filter will pull water and then clean it through a filtration method. The filtration methods include biological, mechanical, and chemical filtration.

1. Biological filtration 

When food leftovers and fish waste are not removed from the water, they become toxic. A biological filter will convert toxic ammonia from decayed food leftovers into nitrite and nitrate.

Nitrate is not very harmful to fish but should be removed through regular water changes. It also plays a major part in the new tank syndrome.

2. Mechanical filtration

In mechanical filtration, also known as physical or particulate filtration, the water is pushed through a filter media that acts as a strainer.

The filter media will catch all the debris. After that, you should clean the filter by removing all the debris and waste it collected. 

3. Chemical filtration 

Chemical filtration uses activated carbon or special resins to remove chemicals, medication, and tannins from the water. Chemical filtration is the best for removing impurities from the water.

Why you should have a filter in a guppy’s tank

Although you can still keep guppies in a tank with no filter, getting one will make a difference in the following ways:

1. Removal of harmful chemicals

It is impossible to see harmful chemicals in the water, but you can confirm their presence by testing the water.

A tank with fish is bound to have ammonia and nitrite spikes due to decayed food and waste, and if not removed, they will kill the guppies. To help clean the tank, you should get a filter.

2. Reduced instances of water change

Having a small tank without a filter is hectic because you must do regular water changes. The guppies will foul the water quickly, and failure to change the water will result in an ammonia spike.

Having a filter will ease things because the filter will clean up, and you just do a water change less often.

3. Oxygenation of  the water

A filter will keep the water moving around, enabling it to absorb oxygen more effectively. Stagnant water has low oxygen and high carbon dioxide levels. High carbon dioxide levels will affect the pH of the water.

A good filter should have the three filtration methods mentioned above. Without them, the filter will not clean the tank effectively.

The filter should also be easy to clean and maintain because it’s meant to ease the burden of cleaning the tank. It should be reliable and able to clean the aquarium effectively.

How long can guppies live without a filter?

Guppies can live all their lives without a filter, depending on how well you take care of them. Without a filter, you must pay close attention to your guppies to ensure they live in a safe environment.

Here are things you can do to ensure the guppies are happy and healthy, even without a filter:

1. Clean the tank regularly

Cleaning the tank of leftovers, dead fish, fish waste, and any other debris is the most important thing to do without a filter. Although guppies do not produce much waste, even the little waste and food leftovers will cause ammonia to spike after decay. Cleaning the tank will ensure this does not happen.

2. Perform regular water changes

A regular water change will remove ammonia, nitrate, nitrite, or other chemicals or debris within the tank. A small tank or a tank with many fish will require more water changes than a big tank or a tank with few guppies.

Buy a test kit and test the water regularly, and ensure to keep all water parameters, including the pH, temperature, and water hardness, at the required levels.

3. Do not overstock 

Keeping more fish than the recommended number, even in a tank with a filter, is dangerous. It’s more hazardous in a tank with no filter.

Overstocking will result in excess waste and low oxygen levels. The excess waste will cause ammonia poisoning. 

4. Add plants to the tank

Plants are important to a guppy tank with no filter. They will be a good surface for useful bacteria to grow on. They also oxygenate the water.

5. Get a bigger tank

A small guppy tank without a filter is a hazard because ammonia poisoning is bound to happen due to fish waste. You should get a bigger tank if you cannot clean the tank regularly and do water changes. A bigger tank will give you more time before fouling up.


Guppies are some of the fish that don’t need a filter, and they can still survive without it. However, a filter is important because it helps aerate and clean the tank. Without a filter, you must clean the tank frequently and do a regular water change, but there will still be the risk of harmful chemicals. 

If you do not intend to use a filter, clean the tank more frequently and perform regular water changes. You should also plant the tank and keep only the recommended number of guppies. However, having a filter will make the maintenance of the guppy tank easier.

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