Do Guppies Need a Filter?

No, guppies don’t need a filter. They can survive in a garden pond or a filterless aquarium provided the tank is mature, has lots of plants, and the tank is stocked very low. While they don’t need a filter, we strongly recommend one for all but the most advanced fish keepers.

Preparing a new tank for your guppies? One of the most basic questions you should ask yourself is, “do guppies need a filter?”

This article addresses the question in more detail. It also answers the question: what do filters do? And how to set up a filterless tank for guppies?

Do Guppies Need a Filter?

Guppies don’t necessarily need a filter, but one is strongly recommended. Guppies are among the few types of fish that don’t produce much waste. They don’t pollute the tank to its fullest. Therefore, they can survive without filters, although a filtering system is recommended.

What Do Filters Do in a Tank?

The primary purpose of filters is to purify the water, where they suck the water from the tank to clean it through different media. They don’t only remove waste but also create a cleaner environment in the aquarium.

Filters have four main tasks:

Mechanical Filtration

This medium removes solid waste, such as feces, dirt, debris, leftover food, and dead plants. It acts like a garbage pin that removes the waste you may see in your aquarium.

Mechanical filtration is the first phase in the purification process. It helps you get rid of the big particles. However, you should clean this medium regularly to avoid overflowing.

Chemical Filtration

This is the second stage of purification. It removes any unwanted chemicals in the tank. It also helps get rid of any discoloration or strange smells in the water.

This process removes tannins that result from plants. Tannins can be good for reducing the water’s PH level. However, in large doses, they make the water discolored or even murky.

Biological Filtration

This is the last and most important stage of filtration. It removes nitrogen compounds and ammonia that dissolve in the water due to the decomposition of fish waste and plants.

The biological filtration medium constitutes a perfect environment for the growth of beneficial bacteria that consumes these harmful compounds.

Ammonia, even in small doses, can be toxic to fish. An ammonia spike can cause the death of your fish. Therefore, biological filtration makes the water safer.

Water Oxygenation

Filters play an important role in oxygenating the aquarium. By moving the water surface, they increase its oxygen level.

Dissolved oxygen is essential for the survival of guppies. In fact, the lack of oxygen in water may lead to the drowning or suffocation of your fish.

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How to Set Up Your Filterless Guppy Aquarium?

If you choose to set up your aquarium without a filter, you should consider the following:

Use a Bigger Tank

The size of the tank matters. Logically speaking, water gets polluted more easily and rapidly in smaller aquariums. Smaller tanks risk reaching an ammonia spike faster.

In general, the chemistry of the water tends to be unstable in small tanks. With no filter, use large aquariums because smaller ones will require frequent maintenance.

You should start with ten gallons of water for three guppies since they reproduce fast, and you don’t want to crowd your aquarium.

Avoid Overstocking Your Tank

Overstocking your tank may be harmful to your guppies. The more fish you have, the more waste there’s in the water, which causes the rapid accumulation of ammonia. This, in turn, may lead to the death of your fish.

Put Live Plants

In addition to adding a touch of natural beauty to your aquarium, live plants can be a natural filter.

Plants can be a good surface for the growth of the bacteria required to get rid of ammonia. Moreover, they increase the oxygen level in the water to create a more suitable habitat for your fish.

Live plants also play a vital role in limiting the growth of algae in your tank. They compete with algae for resources.

Closeup shot of a guppy fish in an aquarium with plants in the background

Perform an Initial Nitrogen Cycle

It’s important to perform an initial nitrogen cycle before adding the guppies to your aquarium. Follow these steps to complete it:

  1. Pour tap water that is free of chlorine and chloramine into your aquarium.
  2. Add flakes and pellets daily for a few days.
  3. Using a good quality test kit, you’ll notice:
    1.  Ammonia will build up.
    2. Nitrites will start to build up, decreasing the level of ammonia.
    3. After a few days, Nitrates will replace Nitrites. Nitrates are less dangerous to fish if kept below 20 ppm.

Choose the Right Type of Substrate

When choosing the type of substrate for your filterless tank, there are two factors to consider:

Ability to Hold Nutrients

Since there are live plants in your aquarium, you should choose a substrate that can hold nutrients for long. Therefore, stay away from sand and gravel.

Easy to Clean

You have no filter, so you’re cleaning your tank regularly. Make your life easier and choose a substrate that would be easy to clean. Again, steer clear of sand.

Green Black Orange Clear Guppy

How to Maintain Your Filterless Guppy Aquarium

Your aquarium is the guppies’ habitat. Taking good care of your tank means a long healthy life for your guppies. Here’s how to do it.

Change the Water Regularly

If you choose not to install a filter, you should check the quality of the water regularly. This way, you avoid the accumulation of waste, debris, ammonia, and other chemicals that may harm your guppies.

You can start with partial water changes. For example, change 25-50% of the water in your tank. Use a trustworthy test kit to check the water parameters.

There’s no rule as to how often to change the water. However, the properties of the water will give you an idea.

Use Ammonia Neutralizers

Ammonia neutralizers turn ammonia into ammonium, which is harmless to fish. This creates a better living environment for your guppies.

Manually Clean the Tank

If you don’t have a filter, you need to clean your tank by hand. It’s not hard to do that. Following are some easy things to do frequently:

  • Scoop out extra food flakes
  • Remove decaying plants
  • Clean the substrate


Do guppies need a filter? No, they don’t. Guppies can survive without a filter under the right conditions.

With no filter, you should take some measures, including using a big tank, inserting live plants, and changing the water regularly.

However, filters are helpful and perhaps essential for beginners. They reduce many risks and save time and effort. A filter oxygenates the water and conducts three filtration stages: mechanical, chemical, and biological.