Fish That Don’t Need Filters or Heaters

Everyone loves to see fish swimming in an aquarium on an office desk or at home.

They make a wonderful scene and they are beautiful to behold. If you decide to have one as a pet then you will likely want to know exactly what you need to take care of them.

You want to know what type of food they eat, if they can live together with other fish, or if they can survive in an aquarium.

In this article, we’ll be discussing fish that don’t need filters or heaters like:

  • Goldfish
  • Betta
  • Guppies
  • Zebra Danios

You may think that all fish tanks must have a filter and heater. Especially when you consider the importance of a filter in keeping the water clean and a heater to maintain the temperature.

The answer to this is that there are fish that don’t need filters or heaters to survive. This makes them a good candidate for a fishbowl or aquarium without a filter and heater.

Fishbowls are cheaper and most people who can’t afford a tank want to know if they can keep their fish inside a fishbowl.

Fishbowls are easier to maintain and require less stress than getting a filter and heater.

Why Do Fish Need a Water Filter?

I would like to explain to you why fish need a water filter first before you decide whether you want to do away with it.

Fish live inside the water and do virtually everything they want to do inside the same water. If fish were human then you can say that the water is their home, their kitchen, their playground, and even their toilet.

Fish don’t go out of the water to do anything including excreting. This is where the problem is.

The fish will not eat all the food that you drop inside the water. The remaining food particles will settle at the bottom of the tank and some will dissolve in water.

This is a major source of pollution in the water and it can be harmful to the fish. Also, the major excretory product of fish is ammonia which they release directly into the water. Ammonia is soluble and dissolves in water but it is also harmful to fish.

The only way to reduce the harm that will be done to the fish is to filter the water to remove the settled dirt and also the dissolved dirt.

There are two main types of filters based on how they work and they are Mechanical and Biological Filters.

  • Mechanical Filters: are responsible for removing particles such as uneaten food from the water.
  • Biological Filters: depend on living organisms like bacteria to break down harmful substances in the water into less harmful substances.

Now you know what a filter is and why you need one.

Water Pollution Level

The level of pollution is dependent on the amount of food given to the fish, the size of the fish, and the quantity of water in the tank.

If you give a small amount of food, then the water will not get polluted on time. If you have smaller fish it means they won’t excrete more waste products than bigger fish and won’t pollute the water on time. The volume of the water in the tank will also determine whether the water will get polluted on time or not.

These are the reasons why some fish can survive without a water filter. Some fish are also hardy meaning that they can survive in unfavorable conditions.

I will provide examples of fish that can live without water filters. But first, let us talk about why fish need a water heater.

Why Do Fish Need a Water Heater?

Fish are cold-blooded animals. What this means is that they rely on the temperature in their environment to control their temperature. This means if the water around them is cold, their temperature will be cold. And if the water in their environment is warm their body temperature increases.

In their natural home, some fish prefer the cold water experience while others prefer warmer water. When you have cold-water fish in your aquarium you don’t need a water heater because the temperature will be okay for them. However, if you live in a cold region and you want to put a warm water fish in your aquarium you will need a water heater.

Now that you understand why you need a water filter and heater, here are some examples of fish that can do without them.

Examples Of Fish That Don’t Need Filters or Heaters

Goldfish: this is one of the most common aquarium fish that does not need a filter and heater. From the name, you can tell that their appearance is gold and that makes them beautiful to look at. They are good for starters as they require little care. However, you will need to change their water often as they can be messy.

Betta: this is another good pet that can survive without a heater and filter.

The Ultimate Guide To Betta Fish

They have radiant colors and they can easily be trained. The only problem with this fish is that they don’t usually get along with other types of fish.

Guppies: if you want to get yourself a fish with many bright colors and can live without a filter and heater then guppies are the answer. They are also easy to train and can live together with other fish.

Endler’s Livebearers: although not as colorful as the guppies they are as hardy as them and can survive without a heater and filter. They are also easy to take care of and they come in different colors too.

Zebra Danios: you can guess what this fish looks like already. They have stripes of black and white and they are inexpensive fish that make a good aquarium pet.


This article has explained all that you need to know about water filters and heaters and fish that can live without them. Although some fish can do without them, it is good to know that water filters and heaters are important accessories If you want to maintain a healthy aquarium.

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