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Do Molly Fish Need A Filter? | The Answer Will Suprise You |

Many aquarists choose mollies because of their vivid colors, small size, and their ability to survive in different water conditions. Although they are hardy fish, do molly fish need a filter?

They do need a filter for the healthy survival of your aquarium. They may live well without a filter, but in certain tank conditions and when properly cared for. How long they can live without a filter is determined by how much you care for them.

In this article, we will specifically talk about this topic along with the uses of filters in an aquarium and how to set up your molly fish tank.

Do Molly Fish Need A Filter

Do molly fish need a filter?

Molly fish are voracious eaters; hence they produce lots of waste in your aquarium.

As you know, excess waste releases more harmful nutrients to your fish, and your tank requires a way to get rid of fish waste to make your aquarium safe for your fish.

A filter is the most efficient way for this. So, unless you have another way to control this Nitrogen cycle, molly fish can not survive in your tank without a filter.

Otherwise, they will die because of Ammonia poisoning. So, molly fish need a filter to thrive in your aquarium.

Can mollies live without a filter?

As we said before, if you have another means of controlling the Nitrogen cycle of your aquarium, your mollies can live without a filter.

But, it is still crucial for you to regularly do a water change in your tank. This way, the waste materials will not accumulate and harm your fish.

Mollies cannot live for a long time without a filter in your aquarium or just a regular water change, so it is really a choice between a healthy fish tank or a thriving molly population in your aquarium.

We do not recommend you to keep mollies without a filter in your aquarium.

How long can molly fish live without a filter?

If you don’t have a filter and do not change the water regularly, the tank gets dirty within about a day.

Mollies can not survive in polluted water for long and die within about 2 to 3 days. However, this depends on other factors like the tank size, if the tank has live plants or not and how many fish you have in your tank.

Ways for mollies to survive without a filter

There are several ways that mollies can live well without a filter.

Live aquarium plants (Natural filters)

When the tank has plenty of natural plants, they work as natural filters absorbing nutrients from the water.

The fish waste becomes fertilizers for these plants, and the plants produce the necessary oxygen for the fish.

As plants naturally clean the water and produce oxygen, mollies can safely live in this environment without a filter.

Bigger tank (More water)

When mollies have plenty of space, it takes longer for the tank water to get dirty.

For instance, if you have a 30-gallon tank with about three fish and do not change the water regularly, it can last up to 7 days before it becomes murky. This is long enough for mollies to survive without a filter.

Regular water changing (DIY filters)

Doing regular water changes is also a way for mollies to live without a filter.

Frequent water changes maintain the nutrient balance in your aquarium and keep it healthy. It removes excess waste and keeps the tank clean.

This way, mollies can survive in your tank for a long time without a filter. However, it will be hard to change the water every day.

Why Use an aquarium Filter in your Molly Tank?

An aquarium filter basically cleans the water so that your fish can breathe in their environment.

As your tank gets dirty, impurities and harmful chemicals contribute to the water causing it to become toxic for your fish.

In a filter, the water passes through different chambers, which have different types of filtration media.

The first chamber collects the larger particles and obstructions while the fine particles are contained later. After this, chemicals that neutralize harmful toxins are added to the water to remove any toxins from the water.

While you can do this job by yourself by performing water changes with vacuum cleaning, the filter does it all the time, saving your time.

It also makes cleaning more straightforward because you can just throw away the filtering media when it gets dirty.

Different types of filters for your aquarium

There are a variety of filters you can buy for your aquarium, and they all work in a slightly different way.

Cannister filter

The canister filter is placed outside of the tank. It is shaped like a cylinder and has filters in it that work with suction.

The water goes inside the filter, and the filtration media is placed outside. These filters are robust and best suited for larger tanks.

Undergravel filter

Undergravel filter is a very effective type of filtration and is placed under the gravel at the bottom of the tank.

The gravel is actually a type of filtration media that inhibits the growth of harmful bacteria in your tank water.

Sponge filter

A sponge filter is placed inside the tank, and it has a sponge in it that catches the particles in the water.

Water passes through this sponge, and the sponge hosts beneficial bacteria which are used in biological filtration.

Hang-on filter

A hang-on filter is placed on the top of your tank, and you put it outside of the tank.

It is a quick and straightforward method to filter your water. These filters are not very powerful but still do a very effective job.

Choosing the Right Filter for your Mollie Tank

All types of filters work well for all types of aquariums. However, you need to choose your filter carefully depending on the size of your tank and the number of fish you have.

A too-small filter for your tank will not remove all the harmful elements from your water, and it can be dangerous to use a too-large filter for your tank.

Internal filters are very popular with fish keepers because they are less expensive than other filters, but they clean the water efficiently.

They are also easy to use and take up less space in your tank, but you need to make sure that it is not placed in essential parts where they can damage your tank.

Sponge filters are an excellent choice for small tanks, and they will not take up much space in your tank.

Cannister filters are expensive, and they need to be placed outside your tank, but they clean the water very efficiently. They also do not take up too much space in the aquarium, and they are easy to maintain. 

When choosing a filter for your molly tank, check for the filter media first. If it is large enough to suck the fish inside, it is better to avoid it.

Molly fish tank setup

By setting up a proper fish tank, you can ensure the optimum health of your mollies while enjoying the aquarium life at your home.

It is up to you whether to use a filter or other ways to clean the water, but we recommend using a filter for your ease.

Mollies are freshwater fish, but they are not uncommon in saline habitats like lagoons and brackish ditches.

These fish can live in freshwater as well as salty waters without any problems. However, they require a temperature between 22 and 27 degrees. So, if you live in a cold area, you need a heater for the aquarium. 

Molly fish need to live in water with high oxygen levels because they are very active fish. So, you can keep a bubbler in your tank to provide oxygen to your fish.

You should also provide mollies with hiding places to feel safe and secure in their tanks. If you are keeping live plants in your tank, make sure you do not place them too close to the light source because they need some light to live.

As for substrate, you can use sand, gravel, and pebbles in your tank. Mollies like to eat small stones and sand that they find on the bottom of the tank. Make sure you clean the substrate regularly because this fish is a messy eater.

What size tank does a molly need?

Mollies are not picky when it comes to tank size, but they will be healthier if you place them in large tanks. You can divide it into separate compartments with barriers if you have a small tank.

If you plan to keep mollies in your aquarium, make sure you have at least 10 gallons for every three molly fish. If you plan to place other types of fish in your tank with the molly, you should consider having more space for this type of fish. 

Can molly fish live in tap water?

Mollies require water hardness between 10 and 20 dGH and a pH level between 7.0 and 8.5.

If the tap water in your region has these water conditions, you can use that water for your molly tank. But tap water in some regions is soft.

Therefore, you should purchase a Water test kit to test the water parameters and make necessary changes to keep your fish healthy.

You can do these changes in two ways: adding chemicals like dechlorinator, using the drip method, and replacing water.

When adding chemicals, you need to remove the carbon from the filter because it does not allow chemicals to dissolve properly and pollute your tank.

If you use the drip method, you need to change 10 percent of your tank water every day until the hardness and pH levels meet the requirements.

If you are planning to use this routine, make sure you have a drip system or a special bucket for this purpose until the replacement is complete.

Final Words

If you want a hassle-free aquarium, using a filter is the best solution to clean the water in the aquarium.

Since mollies, like any other fish, require pristine water conditions to thrive, they require either a filter or any other filtration method to survive in a fish tank. If you don’t want to use an aquarium filter, you can provide a bigger tank with dense vegetation as an alternative.

Further, you can change the water regularly to keep clean water conditions. However, these methods either eat up more space or your time and energy. So, why bother when you have an easy solution to clean the tank?

Credit to : DSBPets
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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.