Do Platy Fish Need A Filter? Can They Survive Without Filter?

Before starting a platyfish tank, you may have an important question lurking in your mind. And, that is whether your Platy fish need a filter or not. See. I won’t compel you into keeping a filter in your tank, considering that you’ve set your tank optimally for your platies to thrive in. But, for the majority of the population, keeping a filter is the best thing to do. And, trust me, your platyfish will thank you for the filter.

While it is not compulsory to keep a filter in your tank, it will be better if you do. Platy fish excrete a lot of wastes. And without a filter, these wastes quickly accumulate and cause ammonia spike which will poison your platies. Keeping a filter has benefits like aeration, growth of beneficial bacteria, and holding the poop, dead leaves, and chemicals temporarily until you come to the rescue.

Of course, you can keep your platyfish in a tank without a filter. But, you need to work 10 times as hard because the platyfish excrete a lot of wastes. Even experts will agree that you will benefit by keeping your platyfish in a filtered tank.

Today, I have answered whether platyfish need a filter, the benefits of a filter, what to do with a filter when a power failure occurs, how you can keep platyfish in a tank without a filter, and many more queries about filters for platyfish. Now, let’s start.

Benefits Of A Filter

You may wonder if the filter has any benefit, if at all. Yes, filters do have benefits. And they are:

  • The good bacteria colonizing the filter is very helpful (Yes, good bacteria grow in a filter with currents). It removes nitrogen and ammonia from the platy tank.
  • Filters trap the poop of your fish temporarily until you deal with it. Without a filter, you have to change the water every day which is a waste of time and energy.
  • The filter can create a light current which is similar to platy’s wild home.
  • The filter’s side job is to help in aerating the water. Aeration is very beneficial for your platy’s growth.
  • Most importantly, you won’t have a high water bill!

So, Do Platy Fish Need A Filter?

I think this question is debatable. Because while platyfish can live without a filter, they will surely benefit if you put a filter.

See, platyfish eat a lot and they excrete a lot of wastes too. These wastes will increase the ammonia and nitrogen levels in your tank. Without filters and live plants, the ammonia spike will quickly poison your platyfish.

Yes, platyfish need a filter. I personally kept a filter for my platyfish and many fish owners agree on keeping a filter for their platyfish.

If you decide not to keep a filter, you have to perform frequent, high-volume water changes every day. Moreover, you need to test the water quality every day with a testing kit. This may ruin your fun of fish keeping and also waste your time and energy. Not to forget the high electricity bill.

How To Choose The Correct Filter For Your Platy Fish?

In the market, you can see many different brands, types, of filters that use different technology.

For example, some filters are best for trapping solid poop, dead leaves, etc. While some have a side job of aerating the water in the tank.

Buy a filter that has a weak current. Low current replicates platy fish’s natural habitat and will make them more active.

A good filter also removes tannins and chemicals from the tank.

Moreover, a filter that contains bio-sponges, bio cubes, balls, cartridges, and such materials will contain lots of surface area for beneficial bacterial growth. These good bacteria help you to remove the ammonia and nitrates in the tank.

In addition, you should buy a filter that has a flow rate of at least five times the volume of your tank per hour.

There are also external and internal filters. You might want to go into details before getting any one of them.

I personally think any filter will benefit your platyfish as long as it has high trapping capacity, high flow rate, generates air current, and has a surface area for the growth of good bacteria. 

Just keeping a filter is not enough. Of course, a filter will help you clear the water temporarily. Moreover, Keeping filter benefits you into working less hard. But, you need to do your part by removing water weekly, and observe. Also, cleaning a filter is equally as important for its efficacy!

What Happens If You Keep Platy Fish Without A Filter?

You decide to keep a filter-less tank for your platyfish. You forgot to keep live plants too. So, what will happen?

I’ve mostly observed that a Platy fish in a filter-less tank is lethargic, slow-moving, has stunted growth, and dies young.

Your platy will excrete a lot of wastes which are rich in ammonia. But, the limited good bacteria living in the substrates will not be able to convert ammonia and nitrogen into harmless nitrates quickly. Day by day, the ammonia level will increase. Ultimately, the ammonia will poison your platyfish, even killing them within a few days or weeks.

Of course, all of this can be prevented if you change the water daily, keep live plants, and so on. But, a tank without a filter without proper care is very dangerous. Remember this.

How Long Can Platy Fish Live for in Aquariums Without Filtration?

Well, the lifespan of a platyfish is 2-3 years in captivity, provided that you give optimal conditions like filters, balanced pH and temperature, water changes, etc. Moreover, 2-3 isn’t a very long lifespan for a fish.

When you decide not to keep a filter, that lifespan decreases to barely a year or a few months. That is, if you’ve provided life plants and cycled your tank properly, and change the water every single day.

If you don’t even do the water changes and put live plants in a filter-less tank, your platyfish will die in a few days or weeks.

Yes, a filter in a tank is really important.

What To Do If Power Failure Occurs?

So, you are a good owner and you have kept filters in your platyfish tank. But, what if a power failure occurs and your filter fails to do its job?


You need to have a generator, inverter, or any backup power with you beforehand. This backup will charge your filter when the electricity goes off. After the power comes back, you can remove the backup immediately.

If the filter doesn’t work or if the switch stops working, you need to unplug the filter. Then, clean the filter as the filter may accumulate waste products. This will be your chance to clean a week or month old filter too. Keep the filter back in. And then, start the backup until the electricity comes back again.

Change Water Everyday In Absence Of Backup

If you don’t have backup power, you can change the water every day. Don’t use cold water. But, use tap water which has been dechlorinated. You need to test the quality of water every day until the power comes back again.

Reduce The Feeding

Another suggestion to you will be to feed your platyfish with less food. Fasting for 2-3 days is actually good for platyfish. And they don’t die or starve without food for a few days. I told you this because more food means more production of wastes.

Since the filter isn’t working, you need your platyfish to generate as little wastes as possible. So that the wastes don’t overload the beneficial bacterium and the plants.

Setup Your Aquarium Without Using a Filter

Although I prefer keeping a filter for my platyfish, you can technically keep your platyfish in a tank without the filter. See, I recommend you to keep a tank without filter only when you have enough experience in the fish keeping hobby. Also, it will require your time and energy to maintain such a tank.

But, if you so wish to keep a tank without a filter, you can do the following:

Cycle Your Tank

You should cycle your tank before keeping platyfish in there. The nitrogen cycle means you’ll allow the growth of beneficial bacteria so that the platy wastes will convert to harmless compounds.

So, naturally, your tank won’t have beneficial bacteria. You need to let the bacteria grow in your tank for 2-3 months before keeping the platies in your tank. Cycling is so necessary that even a filtered tank needs to be cycled.

Thus, You should read about the nitrogen cycle before keeping your platyfish in the tank.

Lots Of Live Plants

Heavily planted tanks are increasing in the fish keeping hobby. And, for a good reason too. For, live plants act as natural filters. They absorb the ammonia and nitrogen and release oxygen and nitrates in your tank. Moreover, your platyfish can feel like it has returned to its wild home when you heavily plant your tank.

If you’re deciding to keep your Platy fish in a tank without a filter, you can invest in living plants, not artificial plants. And make sure to keep lots of them. Most natural aquariums you see will have a plethora of plant vegetation. And in such a tank, filters are not necessary.

Plants like Anubias nana, crypt wendtii, micro sword, Pygmy chain sword, java moss, java fern, hornwort, and Amazon sword will suit your platyfish tank. Make sure to buy plants that don’t heavily depend on the dosing of fertilizers, as this may disrupt the water chemistry of your tank.

Frequent Water Change

The water in your tank should be monitored frequently, especially when you don’t keep a filter. It’s because the water is your platy fish’s home.

With a filter, you need to biweekly or weekly change the tank water. But, without a filter, you need to change the tank water on a daily!

Firstly, start with a 50% water change every week. You also need to check the water condition every day using a testing kit. After testing the water chemistry, you can adjust the water changes as needed. Maybe your tank water needs less change, meaning every alternate day. Or maybe your water condition is really bad that you need to change the water every single day. It depends on the environment of your tank and the water you keep. This is determined when you use a testing kit to know the water chemistry of your tank.

While changing the water, you shouldn’t pour too hot or too cold water. Use tap water that has been dechlorinated. Because tap water contains many hard chemicals like chlorine, phosphorus, manganese, etc. These chemicals will destroy the good bacterium in your tank.

Aquarium Size

If you’re keeping a tank without a filter, you need quite a large tank even for a few platyfish.

The minimum size will be a 30-gallon tank. This is because you need the beneficial bacteria to grow and you need to place lots of live plants. A large tank also ensures a stable ecosystem in absence of a filter.

Avoid Overcrowding

The inch-gallon rule is suitable for a filtered tank. But, the inch-gallon rule falls short for a tank without a filter. SO let’s see what happens if you decide to overcrowd your aquarium:

Platy fish excrete a lot of wastes. The more platyfish you keep, the more they poop. And your tank only has limited good bacteria. All of these good bacteria and live plants will have a difficult time converting their wastes into harmless compounds. Even a frequent water change won’t be able to compete with an overcrowded tank.

Thus, if you decide to keep platyfish in a tank without a filter, you have to calculate the number of fish according to the tank. I think one platyfish that grows 2-3 inches requires a minimum of 5-gallon tank space to swim around. And since platyfish prefer groups, you need to keep 5-6 Platy in a tank. So, you need to get a 35+ gallon tank for 5-6 platyfish. This tank size is just the minimum for a tank WITHOUT a filter.

If you want to keep more Platy fish in a 30-gallon tank, you can use a filter. You know, the advantage of a filter is that you can overstock your aquarium without any bad consequences.

Aquarium Maintenance

Regular maintenance of your tank is necessary for a filtered tank. And this becomes even more necessary when you keep a tank without a filter.

Besides changing the tank water, you need to manually vacuum the floor of the tank to remove fish poop, debris, and uneaten food particles.


Do Platy Fish Need Air Pump?

It’s not compulsory for you to keep an air pump in your Platy fish tank. But, if you have a filter that has an air pump as its side function, it will be better. It’s because the filter will aerate the tank and provide oxygen to your Platy fish.

What Is Lifespan Of Platy Fish?

In your tank, under optimum conditions, Platy fish will live up to 2-3 years on the maximum. Although hardy, platies don’t have a long lifespan.


To sum up, yes, Platy fish need a filter. But, if you balance the tank by keeping live plants, don’t overcrowd the tank, do a frequent water change and so on, you can keep your platy in a tank without a filter. I hope you got the answer to your question.