Do Goldfish Need A Heater? (Heater Watt Size Guide)

Goldfish are cold-water fishes that can survive up to a temperature of 32°F. But can your goldfish adapt to sudden fluctuations in the water temperature? So, do your goldfish need a heater? Let us find out:

Despite being cold-water fishes, some fancy goldfish like Oranda need a heater for their proper growth and development. However, sudden fluctuations in the water temperature can stress both common and fancy goldfish. We advise using a heater for the stable water temperature in your goldfish tank.

The below article will discuss the types of goldfish that need a heater to thrive. In addition, we will also learn about how the sudden fluctuations in the water temperature affect your goldfish.

Do goldfish require heater?

It depends on the goldfish you are placing in your home aquarium. For example, if you are placing a common goldfish, they will not need a heater to thrive.

However, most fancy goldfish breeds prefer a warmer climate, so they need a heater in their tank.

Also read: Do Goldfish Fry Need A Heater?

Ideal water temperature for goldfish

Types of Goldfish Water Temperature
Common Goldfish 68-74°F
Fantail Goldfish75-80°F
Oranda Goldfish65-72°F
Lionhead Goldfish60-75°F
Bubble Eye Goldfish 70-80°F
Phoenix Goldfish 65-72°F
Japanese Tamasaba Goldfish60-70°F
The above table shows the ideal water temperature for different types of goldfish.

Also read: What Is The Ideal Water Temperature For Goldfish?

Which type of goldfish do need a heater?

Some fancy goldfish require a heater in their tank for their well-being. Some of the common types of fancy goldfish that need a heater are as follows:

  1. Lionhead Goldfish
  2. Oranda Goldfish
  3. Tamasaba Goldfish
  4. Celestial Eye Goldfish
  5. Bubble Eye Goldfish
  6. Butterfly Goldfish
  7. PomPom Goldfish 
  8. Froghead Goldfish
  9. Tosakin Goldfish

The above were some fancy goldfish that require a heater in their tank for their proper growth and development. 

Which is the right size heater for your goldfish tank?

Aquarium Size Required Heater Wattage
5 Gallon ( 20 liter)25
10 Gallon (40 liter)50
20 Gallon (80 liter)100
25 Gallon (95 liter)125
40 Gallon (150 liter)200
50 Gallon (190 liter)250
65 Gallon (250 liter)2 X 200 W
75 Gallon (285 liter)2 X 300 W
The above table shows the heater wattage requirement for different sizes of an aquarium.

Which is the best heater for your goldfish tank?

Aquarium SizeRecommended Heater
5 Gallon 25 W (FREESEA 25W Heater)
10 Gallon 50 W (Fluval M50 Submersible Heater)
20 Gallon 100 W (Fluval M100 Submersible Heater)
25 Gallon 125 W (EHEIM 125W Heater)
40 Gallon 200 W (Fluval M200 Submersible Heater)
50 Gallon 250 W (EHEIM 250W Heater)
65 Gallon 2 X 200 W (Fluval M200 Submersible Heater)
75 Gallon 2 X 300 W (Fluval E300 Advanced Electronic Heater)
The above table shows the best heater for your goldfish tank

Can goldfish live in a heated tank?

You can place your goldfish in a heated tank as long as the water parameters required by your fish are fulfilled. 

Most types of fancy goldfish, like lion heads, prefer a warmer temperature in their tank.

In addition, your goldfish are more likely to breed when you place them in a warmer temperature.

It would be best to keep the tank well oxygenated as warm holds less dissolved oxygen.

You can add an air pump to the tank as it helps to increase the tank’s oxygen level by increasing the water movements at the tank’s surface.

We suggest you buy Tetra Whisper Air Pump as it is easy to use and does not produce any noise.

You can purchase it from Amazon Tetra Whisper Air Pump.

Do pond goldfish need a heater?

Your pond goldfish do not require a heater as they can thrive up to a temperature of 40°F.

As the temperature drops below 50°F, pond goldfish hibernate themselves at the bottom of the pond.

Your pond goldfish can even survive in lower temperatures if there is enough oxygen supply in the pond.

You must make sure that if the pond freezes, there is a hole in the ice that allows the oxygen to enter and carbon dioxide to leave the water.

You can use a deicer in such a case. A deicer ensures a hole in the ice if the pond freezes, allowing the oxygen to enter the water and carbon dioxide to leave.

However, if the temperature drops below 50°F, we advise you to place your goldfish in indoor tanks to provide their ideal water temperature.

The ideal water temperature of a goldfish tank should range between 68-74°F.

In the case of a pond goldfish, if you are placing them in a pond, you must ensure that the temperature does not fall below their suggested water parameters as pond goldfish are very sensitive.

A rise or drop in the temperature can lead to severe health issues in your fancy goldfish.

What happens when the temperature becomes too cold?

Here are the changes you will discover in your goldfish if the temperature becomes too cold.

Lethargic

You will discover your goldfish turning lethargic if the temperature becomes too cold.

Your common goldfish will stop eating if the temperature falls below 50°F.

If you place your goldfish in a pond and the temperature drops below 50°F, you should stop providing them food.

In the case of fancy goldfish, the temperature in the tank should never fluctuate as fancy goldfish are sensitive.

Your fancy goldfish can suffer from extreme stress if you do not provide them with adequate water parameters.

Excessive stress further can also lead to the passing away of your goldfish.

Also read: Why Is My Goldfish Lethargic?

Weaken Immune System

A lethargic goldfish will have a weaker immune system that will make them prone to several diseases and parasites.

When the water is too cold, your goldfish will avoid eating, making them weak and fall ill.

Stunted growth.

Placing your goldfish at a too cold temperature can also affect the growth of your fish.

Due to the too cold water in the tank, your goldfish will not prefer to eat much and will not have the energy to grow to their full size.

Therefore, we advise you to provide an ideal water temperature to your goldfish for their proper growth and development.

Also read: Why Is My Goldfish Not Growing?

What happens if the water gets too hot in your goldfish tank?

Here are the changes you will discover in your goldfish if the water in the tank gets too hot.

Eliminate the beneficial bacteria

Too hot water in the tank can eliminate the beneficial bacteria in the tank. The beneficial bacteria in the tank help to keep the ammonia levels low. 

Elimination of beneficial bacteria in the tank can lead to a spike in the tank’s ammonia level that can cause severe health issues like ammonia poisoning in your goldfish. 

Stressed

Too hot water in the tank can lead to extreme stress in your goldfish. 

As goldfish are cold-water fishes placing them in too hot water can weaken your goldfish’s immune system, making them weak and prone to several diseases and parasites. 

Also read: What To Do If My Goldfish Is Stressed?

Oxygen Deficiency

Hot water holds less dissolved oxygen than cold water making your goldfish gasp at the top of the tank’s water surface.

A drop in the tank’s oxygen level can also lead to significant health issues like losing appetite in your goldfish.

Therefore, it will be advisable to keep eyeing the tank’s water temperature for the well-being of your goldfish.

We advise you to use LCR Hallcrest Vertical Aquarium Thermometer as it is easy to read and provides accurate results.

You can buy it from Amazon LCR Hallcrest Vertical Aquarium Thermometer.

Also read: Can Goldfish Live Without Oxygen?

How does unstable water parameters affect your goldfish?

Unstable water parameters affect your goldfish in the following ways:

  1. Unstable water parameters can weaken your goldfish’s immune system, making them prone to several diseases and parasites.
  2. Unstable water parameters can make your goldfish lose its appetite.
  3. Unstable water parameters can shock your goldfish leading to excessive stress in your fish.
  4. Inadequate water parameters can affect the growth of your fish.
  5. Wrong water parameters can make your goldfish fall ill.
  6. Low pH in your goldfish tank can make the water highly acidic, eventually burning the skin of your goldfish.

Therefore you should always provide adequate water parameters in your goldfish tank for the well-being of your fish.

ParticularsGoldfish
Water Temperature68-74
PH Level7.5
Ammonia Level0-0.25ppm
Nitrate LevelBelow 40 ppm
Nitrite Level0 ppm
TDS Level170-250ppm
The above table shows the ideal water parameters for your goldfish tank.

Also read: Ammonia Poisoning In Goldfish

Conclusion:

  1. Common goldfish do not require a heater, whereas some fancy goldfish breeds need a heater for their well-being.
  2. The ideal water temperature for your common goldfish ranges between 68-74°F.
  3. Your goldfish can live in a heated tank as long as the water parameters required by the fish are fulfilled.
  4. Placing your goldfish in too cold water can make them lethargic and affect the growth of your goldfish.
  5. Too hot water in your goldfish tank can eliminate the beneficial bacteria, lower the tank’s oxygen level and make your fish suffer from stress. 

Reference: ResearchGate

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