Can I Put a Heater in My Goldfish Tank in Winter?

Goldfish, despite their simple nature, can be a baffling fish to keep in the midst of times! We’ve all had the pleasure of seeing an inaccessible Goldfish bowl or a pond that is outdoors.

What do you think of your Fancy Goldfish – – is your adorable Moor or Shubunkin really shivering and calling for warmth? If you’re keeping these delicate Fancy Goldfish, a small heater is a great option to keep your temperature in check.

Can I Put a Heater in My Goldfish Tank?

Should I Put a Heater in My Goldfish Tank in Winter? It turns out that the answer is either yes or no! It all depends on two things:

Factors That Determine Whether A Goldfish Needs A Heater:

Two aspects determine if the goldfish tank requires a heater. The breed of goldfish and the place where it was raised.

What Breed is Your Goldfish?

Certain fish thrive on freezing cold water, whereas others prefer warmer waters. Here are the various best temperatures for the goldfish species.

Many goldfish owners are baffled at this point: Can I Put a Heater in My Goldfish Tank in Winter? Certain owners say yes, while others say a non-serious no.

Which One is It?

The answer is right. Goldfish thrive in colder waters. However, some species of goldfish require an aquarium heater and others do not.

How do I keep my goldfish warm in the winter? This article explains everything that has to do with heating and goldfish. It provides the optimal temperature for goldfish and goldfish species that require heaters and the negative effects of keeping goldfish in tanks that are not at the right temperature.

Read more.

What is The Ideal Water Temperature For Goldfish?

The optimal setting for the temperature of goldfish varies on the type of fish.

Goldfish are considered to be cold-water fish, which can live in temperatures of 60 to 78 degrees Fahrenheit.

Goldfish are happier and healthy in tanks that have an even temperature, either whether or not they have the use of a heater. If you notice a rapid rise or dip in temperatures, it is ideal to invest in an aquarium heater.

Goldfish SpeciesOptimal Temperature (F)
Common Goldfish60-75 degrees
Phoenix GoldfishFrom 65 to 72 degrees
Fantail Goldfish75 – 80 degrees
OrandasFrom 65 to 72 degrees
Lionheads60-75 degrees
Tamasaba60-70 degrees
Bubble Eyes70 – 80 degrees
Comet Goldfish60-72 degrees
Shubunkin GoldfishFrom 65 to 72 degrees
Japanese Wakin60-78 degrees
Jikin Goldfish65-78 degrees
Moor Goldfish50-75 degrees

You may be surprised, but the kind of Goldfish you own will dramatically influence how cold-hardy they will be. There are hundreds of in a variety of Goldfish.

If you own a Black Moor, Shubunkin, or Oranda as well as a feeder Goldfish they are all technically Carassius auratus. It is a small carp that originates taken from East Asia.

This means that they can be able to interbreed effortlessly and share the same requirements.

All Goldfish are temperate fish that do not require a heater in contrast to fish like Discus that originate from tropical climates that are hot and humid.

However, Fancy Goldfish sometimes can’t take abrupt temperature changes as their predecessors did and they almost never drop to freezing.

If you’re keeping these delicate Fancy Goldfish, a heater is a great option to keep your temperature in check.

However, you shouldn’t allow the temperature of your water to rise far above 75 degrees; in fact, 68 to 72 is the best temperature for them and their gentler-bred relatives.

If your home is kept at a moderately warm temperature, you might not require an additional heater, even to keep warm Fancy Goldfish.

If the temperature is likely to fluctuate towards colder temperatures than this, I suggest having a heater in order to keep the water from getting too cold.

The search for an efficient heater can be an issue due to the number of options available.

Goldfish That Should Have a ‘Heater:

  • Orandas
  • Moors
  • Telescope Eye
  • Lionheads
  • Bubble Eye
  • Pom-Pon
  • Other Fancy Breeds

Cold-Hardy Goldfish:

  • Comets
  • Shubunkins
  • Common/Feeders
  • Japanese Wakin
  • Other breeds that are closer to Wild-type

It is clear that different goldfish require different temperatures for their water by looking at this table. Goldfish thrive in cold water out in the open.

However, fancy goldfish require an environment that is warm as they are less fragile.

Phoenix goldfish Fantail goldfish Orandas, Bubble eyes, and lion heads are all fancy goldfish species that require heaters.

Fantails thrive in temperatures ranging from 75 to 80 degrees. The lower temperatures are the upper limit for goldfish.

It is therefore essential to install tanks with heaters to keep the temperature of the tank.

Bubble eyes also need an aquarium heater in order to keep the water’s temperature in the range of 70 to 80 degrees.

The fancy goldfish are sensitive to temperature fluctuations. Because of this, you should put them in a secure heated tank and not an unheated goldfish bowl.

Orandas also go shocked when they are kept in lower temperatures. They require stable temperatures of 65 to 72 degrees.

What Conditions were They Raised in?

Goldfish are considered to be temperate fish. But, there are some that are raised with other tropical fish such as betta fish, tetras livebearers, and guppies.

This means that they have been adaptable to living in warmer water temperatures.

If you take a fish back home, it is essential to include a heater in your tank. Extreme temperature fluctuations could cause the goldfish to experience shock, which can cause permanent harm or even death.

If you would rather keep your goldfish in cooler waters you can use a heater during the initial days to recreate the conditions that the fish adjusted to.

Then, reduce the temperature of the tank by dropping it one degree each day. By doing this, you will avoid causing stress and health issues for your goldfish.

Fancy Goldfish like Telescope Eye or Black Moors have been kept in stable conditions in aquariums for a long time now.

A lot of them are raised in tropical environments with Livebearers Tetras and other traditional tropical fish.

If you are certain that your Goldfish was kept in warm, soft temperatures, don’t overheat the fish by abruptly placing them in an unheated fish tank.

Allow them to adjust, and bring the temperature down by a degree every day or until you’re at the ideal temperature.

I would not recommend the keeping of Fancy Goldfish below 60, particularly those with large bodies who have been in heated aquariums for the entirety of their life.

How to Choose an Aquarium Heater

We’ve now established that certain species of goldfish require heaters, so let’s look at the best way to locate one.

When you are choosing a heater be sure to check the power consumption. The standard rule is that it should be at least three to five watts per gallon.

Furthermore, the heater must be able to provide even heating to the tank.

The majority of aquarium heaters have suction cups that secure them on the glass walls of the goldfish’s aquarium.

These are the kinds of heaters available:

Hanging/Immersible Heater (External Heater)

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They are the most commonly used heaters. They are placed on the tank to ensure its heating component rests directly on the surface of your water. Hanging heaters offer basic heating, but they aren’t the most efficient.

Hydor ETH 200 In-Line External Aquarium Heater, 200w, 1/2" hose
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Last update on 2023-09-19 / Affiliate links / Images from Amazon Product Advertising API

Submersible Heaters

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Submersible heaters work by submerging them into their waterline. It is equipped with a heating element that is enclosed in glass or plastic that is used to heat the water that flows into the tank.

Submersible heaters are better than the immersible heater.

Cobalt Aquatics Neo-Therm Pro Aquarium Heater (50 watt), Fully-Submersible Freshwater, Saltwater, Thermostat, Thermometer, Shatterproof
  • Electronic thermostat from 68°F up to 94°F, accurate to ±0.5°F
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Filter Heater

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The heater warms water as it goes through the filter system. Certain power filters and canister filters come with an element of heating.

OASE Indoor Aquatics Filtosmart Thermo 100, Black
  • The filtosmart thermos 100 has an integrated heater in compact filter design
  • The built-in heater provides your aquarium with Precise and uniform temperature levels while the...
  • Two stage filtration of biological and mechanical filtration are integrated in this compact design
  • External filter operates quietly to circulate and filter your aquarium water
  • Compact design with large filter surface

Last update on 2023-09-19 / Affiliate links / Images from Amazon Product Advertising API

Substrate Heaters

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Although they are expensive and rare Substrat heaters aren’t expensive, they can help keep steady temperatures in tanks.

The heaters distribute heat to the substrate in order to keep your water at a comfortable temperature.

Hydor 75w Hydrokable Substrate Heater, 25' - for Aquariums 32-53 gal
  • Suitable for tropical aquariums and terrariums
  • Heating cable with suction cups for perfect positioning
  • Works completely safe submerged in water or in a dry habitat
  • Totally safe - double silicone insulation guarantees total safety
  • 75W, 32-52 gal aquariums

Last update on 2023-09-19 / Affiliate links / Images from Amazon Product Advertising API

Can I Put a Heater in My Goldfish Tank in Outdoor Ponds During Winter?

Actually, not so much. Goldfish in ponds can thrive at lower temperatures, even when temperatures drop to below 50 degrees during winter.

If the temperature drops the goldfish’s body temperature is in line with the temperature of the pond.

The lower temperatures cause goldfish outdoors to show an insufficient metabolism. They are less hungry and enter hibernation.

In this period, refrain from feeding your goldfish because they’re not taking in food.

Furthermore, food leftovers can only pollute the pond, causing water quality issues.

What happens if the top of your outdoor pond gets frozen? Does your cold-water fish require a heater? You’ll need a pond heater or a de-icer.

A de-icer makes an opening that allows gas exchange that prevents your goldfish from becoming suffocated and dying.

Pond Goldfish are a little different in their requirements. Because the majority of outdoor ponds (except the container ponds) are far too large to heat effectively, we believe the Goldfish are able to withstand at the very least temperatures in summer.

In the winter months, it is common to bring them inside when the pond gets too deep and is in danger of freezing.

In the majority of temperate countries in the world, as long as your pond has a minimum of 3-4 feet at the deepest part of the pond, your Goldfish can stay in hibernation throughout the winter months.

As I mentioned earlier, Goldfish and Koi are temperate fish. China along with Japan isn’t the warmest in the winter!

If there is an opening in the ice to allow carbon dioxide and oxygen exchange the fish can stay in the pond easily.

If you’re worried about the temperature outside in winter then you could bring your goldfish inside.

But, you can add an electric water heater to increase temperatures to a comfortable level. If you have the most beautiful goldfish, consider adding an electric heater in the winter months.

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This is the place where the pond heater comes into play. It is often called”de-icer” or “de-icer,” these electric heaters open a hole within the ice to ensure that your Goldfish aren’t dying from the absence of oxygen.

You may think “but why don’t wild fish need a hole in the ice?” The reason is that the bodies of water that are outdoors are vastly bigger than the backyard pond.

They also have much lower densities of population.

Nature-based ponds, therefore, keep plenty of oxygen in the winter months to maintain their population of animals. But a pond made by humans with lots of fish will require some help from you!

What Happens If Water is Too Cold For Goldfish?

Common goldfish are considered to be cold-water fish, however, their water temperature must not fall below 50 degrees F.

This is the most extreme range for all goldfish caught indoors. Goldfish that are common and slim-bodied can withstand these frigid temperatures, but they can stop eating and enter hibernation.

Additionally, certain breeds are unable to endure frigid temperatures. Goldfish with fancy names, For instance, are not able to survive temperatures below 55 degrees.

The low temperature can cause health issues like blood clots and other blood clots that affect these goldfish that looks fancy.

Temperatures ranging from 50 to 60 degrees can cause your fish to stop being active. Fish are cold-blooded and their body temperature is influenced by the environment they live in.

If temperatures become too cold their metabolism slows and they go into hibernation.

This is why you’ll see your goldfish swimming at their bottom in a slow manner. They’ll be barely moving until temperatures begin to increase.

What Water Temperature is Too Hot For Goldfish?

However, temperatures of more than 80 degrees are too hot for goldfish. This species of cold water feels stressed due to these conditions as warm water is less concentrations of dissolved oxygen.

The goldfish look for oxygen in such temperatures.

To prevent this from happening, keep the goldfish tank away from radiation and direct sunlight.

Also, ensure that you keep your goldfish in an indoor aquarium in order to maximize the absorption of oxygen.

Big tanks feature a bigger surface area, which allows more oxygen into. If you want to, consider getting an air compressor to aerate the water.

The higher temperatures can also lead to greater growth for the goldfish. They’ll not just become more active and develop faster but also consume more food excrete more, and create a greater bioload.

This can increase ammonia, nitrates, and levels of nitrites in the aquarium.

This can result in ammonia burns or infections when the water quality isn’t kept up.

What Happens When Temperatures Change Suddenly?

If the climate is one that your Goldfish is in, whether it’s a pond, bowl or aquarium is changing rapidly in temperature, heating is a beneficial idea.

Changes in temperature typically happen gradually as the sun moves or with the changing of seasons.

Extremely low and high temperatures can be dangerous for goldfish, however, so can sudden temperature changes.

The fish will experience temperature shock and die. fish within minutes. If your goldfish fail to suffer from shock, they could end up with permanent damage.

In addition, sudden temperature fluctuations cause respiratory issues. If the temperature increases rapidly the oxygen levels in the tank of fish decrease rapidly and make it difficult for the goldfish to breathe.

Additionally, imagine that the temperature suddenly decreases while your fish is eating their stomach.

Colder temperatures lower the metabolism rate, which means the fish won’t be able to take in the food as quickly.

This could be fatal for your fish as the food they have not digested could begin to decay in their stomachs.

This is why it is important to always ensure the constant temperature of your tank regardless of whether you have heaters or not.

Here are some more suggestions regarding caring for goldfish in this video on YouTube:



Do Goldfish Need a Filter?

Always have a filter installed in your goldfish pond or tank. Goldfish are omnivores and generate a large amount of waste. This could pollute the water they drink. If you don’t have a filter the water in your aquarium will quickly cause harm to your fish.

Do Goldfish Like Heated Water?

A tank’s temperature between 20 and 23 degrees Celsius (68 degF-74degF) is the appropriate temperature for goldfish. The temperature should be enough to promote rapid growth, without becoming too high that your fish get stressed due to hot water and low levels of oxygen.

Can a Goldfish Live in a Tank With a Heater?

In essence, goldfish can live in a variety of temperatures. They will thrive in tanks heated like they do at normal room temperatures. For fancy goldfish, the water shouldn’t be heated above 75 degrees F. This is due to the fact that they thrive in temperatures of 60 and 72 degrees F.

Do Goldfish Prefer Warm or Cold Water?

Goldfish prefer cooler waters between 62-74 degrees F. Goldfish are able to be tolerant of temperatures that are higher or lower than the range. The most important thing to keep goldfish healthy and happy is to ensure a steady temperature. Goldfish are stressed and susceptible to illness in fish when the temperature of the water is not constant.

What are the Effects of Sudden Temperature Changes on Goldfish?

The sudden changes in temperature can lead to the development of diseases like fin rot and Ich. Changes in temperature also strain cold-water fish.

Do Goldfish Need a Heater During Winter?

It is contingent on the species. Common goldfish can withstand the winter cold without heating. However fancy goldfish are much more sensitive and require heating to ensure the temperature. Goldfish with fancy colors can become stressed and have a weak immune system and infection when they don’t have an environment that is heated.

Do Fantail Goldfish Need a Heater?

Yes. They, just like fancy goldfish, like temperatures of higher than 60 degrees. A heater can help maintain constant temperatures during the day and evening.

How Can I Test Water Temperature in a Goldfish Tank?

An Aquarium thermometer can determine if the temperature of your tank is within an appropriate level for cold water fish. It is possible to add an underwater, standing thermometer, or a digital one to your goldfish tank.


Can I Put a Heater in My Goldfish Tank in Winter? in winter? Goldfish don’t require heaters the majority of the time.

If the climate of your house or outdoor surroundings is too cold for a fancy or normal Goldfish You may require the help of a heater.

Keep in mind that Goldfish are considered to be endothermic which means the way they function is controlled by their external environmental conditions.

Pick a temperature that’s not too cold or hot (60-75) to ensure that they stay well-nourished and flourishing.

The heating elements can help maintain the temperature of the water, or to prevent excessive ice from developing in the winter.

A heater is an excellent choice to ensure that your cool pets are healthy and worth looking at!

The cold-water fish are able to survive at temperatures of 60 and 78 degrees Some even survive in temperatures that are colder than 50 degrees.

But, you can add an electric water heater to your elegant goldfish tank. They thrive in warmer temperatures but are sensitive to water temperatures that are cold.

As an owner of a goldfish, it is your responsibility to decide if your goldfish require an electric heater or not.


Dibyajyoti Bordoloi is the creator and author of, a third-generation experienced fish keeper and owner of a successful pet breeding farm. He is also a member of the Center for Wildlife Rehabilitation And Conservation (Assam), the Marine Aquarium Societies of North East India, and the Kaziranga Nature Conservancy of Assam.