Do Goldfish Need A Heater? – Ideal Tank Temperature

Winter comes with cold weather, and it can affect your goldfish’s health. So a question comes to your mind: Do goldfish need a heater? Which heater is fine for your goldfish, and how should you set it up? There’s no one around to pick their brains about it? Don’t be concerned; you’ve come to the right place. We are going to show you everything you need to know below.

Do Goldfish Need A Heater?

Yes. But it depends. You can see that some goldfish can thrive and live healthy lives without a heater, and you wonder if yours can. But it doesn’t depend on whether they are goldfish or not. It’s all about the factors in the environment. The ideal temperature range for goldfish is between 60 and 78 degrees Fahrenheit (or 15-25 degrees Celsius).

Obviously, if you live somewhere with a good natural temperature and are suitable for goldfish already, the heater is not a compulsory item for the tank.

With or without a heater, Goldfish thrive and stay healthier when their tank is kept at a steady temperature. It might be preferable to get an aquarium heater if you see rapid increases or decreases in temperature.

Which Factors Determined Do Goldfish Need A Heater?

We all know that heater is needed with goldfish, but it depends. Let’s see the factors that determine whether your goldfish require a heater. There are 3 main points: the breed, where the goldfish was raised, and the tank size.

Goldfish breed

In the wild, goldfish inhabit cold waters. Unbelievably, the type of Goldfish you have will significantly impact how cold-hardy it can be.

Goldfish come in dozens, if not hundreds, of distinct varieties. All varieties of feeder goldfish, including Black Moors, Shubunkins, and Orandas, are technically Carassius auratus, a tiny carp originating in East Asia. As a result, they can easily interbreed and have very similar needs. Unlike fish from the humid tropics like Discus, all goldfish are temperate fish and don’t necessarily need a water heater.

Fancy Goldfish

However, fancy goldfish rarely go below freezing and cannot always withstand sudden temperature changes like their forefathers. If you keep fancy goldfish, a heater can help you keep a consistent temperature in your tank.

A heater is a good choice for:

  • Orandas: 65 to 72 degrees.
  • Japanese Tamasaba goldfish: 60 to 70 degrees.
  • Moors: 50 to 75 degrees.
  • Lionheads: 60 to 75 degrees.
  • Bubble Eye: 70 to 80 degrees.
  • Most other fancy breeds, like phoenix goldfish.

Temperatures between 75 and 80 degrees are ideal for fantail goldfish. For some goldfish, their higher range is their lower range of temperature. To maintain their temperature, as a result, a tank heater must be added.

bubble eye goldfish
Bubble Eye Goldfish in the tank.

Where the goldfish raised

Temperate fish contain goldfish. Some goldfish are, however, raised in tropical fish ponds with betta fish, tetras, guppies, and other livebearers. This indicates that they have adapted to life in warm water.

You must include a tank warmer if you bring such fish home. These goldfish may experience shock from exposure to abrupt temperature fluctuations, which could result in irreversible harm or even death.

Tank size

Larger tank, additional heating requirements. Although tank size is not really important, the larger surface area may need the heater to serve the ideal temperature for goldfish. The tank is divided into 3 parts of the temperature range. The mild temperature is between the top and bottom of the tank. You can remedy this issue and low temperature with an air pump. It also helps to maintain oxygen levels too.

But if your aquarium has a smaller surface, like a typical goldfish bowl may don’t need a heater at all.

typical goldfish bowl
A typical goldfish bowl may not need a heater.

How To Choose A Goldfish Heater?

Now, it’s vital to choose the suitable one after knowing about the breed of goldfish and some more factors that affect the decision to use a heater.

First, when choosing a heater, you should check its wattage. Generally, the rule is 3 to 5 watts for every gallon of water as a minimum. Then, providing evenly heated to the tank is also crucial. Most aquarium heaters have suction cups to hold them against the glass or aquarium walls. Let’s check some below.

typical tank
A typical tank for goldfish indoors.

Some types of heaters for your goldfish

  • Hanging/Immersible Heater: A basic one for goldfish indoors. The majority of heaters are just like that. The heating element is placed on the water’s surface by hanging them on your tank. The heating element will be immersed in the water, and the heater will dangle over the top of the tank. To accommodate the heater’s design, you must drill a hole in the top of your tank.
  • Submersible Heaters: An under-the-water heater operates by being submerged. It has a heating element housed in strong plastic or glass. Compared to an immersible heater, a submersible heater is more effective. Its heating element is frequently enclosed in a glass or reinforced plastic tube, though it can shatter in hot temperatures. The top of submersible heaters is conveniently equipped with LED lights that show when the warmer is on.
  • Filter Heater: This heater warms the water as it flows through the things. This heating mechanism is found in several canister filters and power filters.
  • Substrate Heaters: Substratum heaters support steady tank temperatures while being rare and expensive. To keep the water warm, these heaters heat the substrate uniformly.

Do goldfish tank mates need a heater?

goldfish and tank mate
Goldfish and the tank mate.

Goldfish are social fish, so it’s easy to see they have different tank mates. Small notice that goldfish are cold water fish, so their tank mates have the same requirements. You should remember that warm water fish are so popular in the shop. They can’t live in the same tank.

So this is where a heater takes place. You can use the heater to maintain the temperature on average. In that way, these different types of fish can cohabit. The most important thing is their requirements so that you can adjust to an ideal environment.

How To Set Up A Heater?

  • Find the right spot: It should be positioned where water enters and exits, according to experts who advise fish keepers. Doing this will heat the water uniformly, and the tank’s temperature will be maintained.
  • Set up the heater: Install the device once you’ve located the ideal location. Once it is in place, give it a few minutes to settle to ensure the glass shell can resist temperature changes. Now turn it on, and you can modify the temperature as necessary. After every six hours, adjust consistently if it is within the required range. To ensure it can keep the temperature within a given range, leave it on for around 24 hours.
  • Check: Use an aquarium thermometer to determine your aquarium’s temperature. These tiny, low-cost instruments are made to measure aquarium water temperatures. Additionally, a heater for aquariums with a built-in thermometer is available.
  • Adjust: The aquarium’s location is one aspect that will affect the temperature inside the tank. For instance, if you have an aquarium placed in a space with little to no air movement and a lot of sunlight, the water temperature will rise. On the other hand, the water will stay colder if the tank is placed in a dimly lit area with good ventilation.

What if the temperature is too hot?

For goldfish, temperatures above 80 degrees are too hot. Since warm conditions have lower quantities of dissolved oxygen, these cold water species feel stressed under these circumstances. At such high temperatures, goldfish gasp for breath. Place the goldfish aquarium away from radiators and direct sunlight to prevent this.

To increase oxygen absorption, keep your goldfish in a large indoor aquarium. Purchase an air pump as an alternative to the kind of water. High temperatures also cause problems for your goldfish. They’ll consume more, waste more, and cause a higher bioload in addition to becoming more active and growing more quickly. The fish tank’s levels of ammonia, nitrates, and nitrites will rise as a result. If the water quality is not maintained, it can result in illnesses and ammonia burns.

What if the temperature is too cold?

do goldfish need a heater
Goldfish swimming in the tank.

Although common goldfish are considered cold-water fish, their water shouldn’t be any colder than 50 degrees F. This is the highest limit for any goldfish kept inside. Additionally, certain breeds cannot endure extreme cold. Because of the low temperature, these elegant goldfish suffer from health issues, including blood clots.

Your fish will become inactive at temperatures between 50 and 60 degrees. Fish’s body temperature depends on their environment because they have cold blood. Their metabolism slows down under extreme cold, causing them to hibernate.

As soon as you see the signs, you should have warmer water. Raise temperatures to need heaters.

What if the temperature change suddenly?

Both extremely high and low temperatures, as well as abrupt changes in temperature, are harmful to goldfish. The fish will experience temperature shock and die shortly. Your goldfish could sustain lasting harm even if they do not pass away from shock.

Additionally, abrupt temperature fluctuations lead to respiratory issues. The oxygen in the fish tank quickly depletes when the temperature rises, making it difficult for the goldfish to breathe. So it is important to keep the constant temperature.

Do Goldfish Need A Heater Outdoor

The requirements of outdoor goldfish are a little different, especially in cold winter. Even when the temperature drops below 50 degrees in the winter, common pond goldfish may flourish there. The outdoor pond has a slow metabolism because of the chilly temperatures. They consume less food and soon enter hibernation. Your goldfish won’t be able to digest food during this time, so avoid feeding them. Additionally, the remaining food will contaminate the pond, leading to water quality issues.

But happens if the pond freezes? You will require a de-icer or pond heater. Your goldfish won’t freeze and die since a de-icer makes a hole in the ice for gas exchange.


Do goldfish need a heater in winter?

In the cold, common goldfish don’t need to require a heater. They can withstand temperatures lower than 22 °C. If your aquarium is outdoors, you should get a heater because the temperature could drop to minus 1 centigrade.

Can you put goldfish in a heated tank?

Yes. You may place your goldfish in a heated tank, but keep an eye on the temperature. Additionally, placing goldfish in a warm aquarium will increase their breeding rate. On the other hand, placing goldfish in a warm aquarium may shorten their longevity due to increased metabolism. By increasing water flow and subsequent water oxygenation, this problem might be lessened.

How can I test the water temperature in a goldfish tank?

Auquarium thermometer. If the tank temperature is within the acceptable range for your cold water fish, an aquarium thermometer will be used to check. You can add a floating, standing, or digital thermometer to the goldfish tank.


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