Do goldfish need a heater

Do goldfish need a heater ?

Do goldfish need a heater?  

Having regulated and constant water temperature is very important for the comfort and success of your goldfish in the aquarium. Having a Heater is one of the best ways to control and regulate the temperatures. Goldfish can survive without one but if needed then it becomes useful.

There are some goldfish, especially the small bodied, which don’t need high temperatures. Some will not survive temperatures below 50° F due to issues with blood clotting.

A heater is needed where the tank is freezing cold like during the winter season. A heater is not suitable for huge tanks. One of the reasons why goldfish do not need a heater is because they are cold water species and does well at room temperatures.


The goldfish tank temperature

There are some fish as stated at the beginning of this article which fancy very cold temperatures while others like fancy goldfish are slightly suitable for warm temperature. Aquarium thermometer is an instrument used to measure the temperature of water in the tank. There are three types of aquarium temperature thermometers.

  1. One that sticks inside the tank
  2. One that sticks outside the tank and
  3. The digital thermometer.


An aquarium thermometer that floats on water is preferred because of its accuracy. 

What is the best goldfish tank temperature?

Answering this question will in a great way help us understand our main question, do goldfish need a heater?  The right temperature for your tank is determined by what you intend to use the tank for, is it to breed your goldfish or for other purposes? If your intention is to breed your goldfish, then, you can replicate the temperature changes occurring naturally.

Lowering the temperature of your tank during winter season to around 20°C /54°F encourages your goldfish to lay eggs. To induce breeding hen the water temperature should be raised to between 20°C/68°F and 23°C /74°F.  What of Non-breeding tank temperature? If you are not breeding your fish then you are advised to keep your tank at a steady temperature. The tank temperature should be 23°C/74°F.

You are cautioned never to place your tank in direct sunlight or near radiators. This is to allow your water temperature to remain below 27°C/80° F level. Any temperature warmer than this will stress your fish. Goldfish survives in water that is nearly freezing cold, thus, keep your tank temperature above 18°C /65°F for stronger growth. Fortunately, at optimal temperature, there are no sudden changes in temperature of the tank.

Sudden changes in temperature can stress your fish too or cause some illnesses such as swim bladder. Temperature is another consideration when choosing other fish to live with goldfish. Go for goldfish tank mate compatible with the temperature range as well as the conditions of other tanks.


What of the air supply? Whenever your goldfish water gets warmer/hotter, then you should realize that there is a reduction in the level of oxygen in water. Since Oxygen is vital for your goldfish, get noted that your tank will require adequate aeration system. The adequate aeration system gives water an additional air. Tanks with large surface area are recommended for use than the tall tanks which have poor surface area to volume ratio.


The best Heater for goldfish tanks 

iPower Under Tank Heat pad

This hater is known for its heat uniformity, the heating film, and insulation effectively increase heat transfer with uniformity across the mat, in turn, helping reach the desired temperatures in the shortest time. The heater has a strong grip thanks to the 3M Adhesive Paper of the heat mat which ensures the heat mat stays exactly where it’s needed.


  • Improved Design for overall heat transfer
  • 3M Adhesive Paper for optimum heat transfer
  • Safe and Energy-saving 
  • Easy to Use 
  • LED indicator lights
  • Fahrenheit or Celsius
  • Grounded Outlet 


  • Easy plug-In operation
  • Choice of Celsius or Fahrenheit readout
  • Heat Uniformity


  • Temperature control is only 40°F – 108°F (5-42°C) 

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Hydor Submersible Glass Aquarium Heater

This aquarium heater is safe and very effective. The heater has unique and exclusive heating technology that combined with quality components ensures you are getting the best product, it durable, submersible and you’ll never get thermal shocks. Other great features include high resistance to impact, a graduated scale, and vertical and horizontal positioning.


  • High resistance 
  • Shock resistant 
  • Vertical or horizontal positioning 
  • Graduated scale 


  • No damage in case of running dry 
  • Submersible
  • No thermal shock


  • None

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ViaAqua 300-Watt Quartz Glass Submersible Heater

ViaAqua 300-Watt Quartz Glass Submersible Heater is a high-quality heater. It has a break-resistant construction, its fully submersible and very easy to use and install. It’s available in different sizes and has suction cups for a secure anchor on the aquarium. The heater can be used in fresh or saltwater.


  • High Quality and Break Resistant
  • Quartz Glass Construction
  • Totally submersible
  • Installation is easy
  • Available in different sizes
  • Suction Cups for anchoring
  • Temperature Setting is visible
  • Fresh and Saltwater


  • Waterproof Double Insulation
  • Visible settings
  • Works in fresh and salty water


  • Must be fully submersed

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Eheim Jager Aquarium Thermostat Heater

We all know that a precisely controlled and constant water temperature is very important for the comfort and success of inhabitants. if someone asked Do goldfish need a heater?  this is the heater to recommend. This is an ultra-modern electronic thermal device made for both fresh and salty water. 

The Shatterproof glass construction is one of the best features, it resistant to chemicals and can withstand extreme temperature fluctuations. The TruTemp Dial adjusts temperatures from 18° to 34° C (65° to 93° F). with a control accuracy is +/- 0.5° C.The Thermo Safety Control -makes it possible for ‘running-dry’ protection. The heater shuts off when removed from the water.


  • Shatterproof glass construction
  • Thermo safety control
  • On/off indicator light
  • Comes with mounting bracket and suction cups
  • 5.6 foot cord


  • Resistant to chemical and biological substances
  • Handles and withstands even extreme temperature fluctuations
  • On/Off Indicator Light eliminates guesswork


  • Accuracy is not to the dot since the control accuracy is +/- 0.5° C

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Goldfish live in a cold water habitat but fancy goldfish are delicate, with weak immune system which needs slightly warm temperature. If not, the fish becomes more stressed. The goldfish are prone to bacterial infections and lower tolerance to disease.Mid-high temperature of 70 to 80° F is efficient to allow retainage off of dissolved oxygen in the water. These temperatures are good for the growth of goldfish. If your tank isn’t that warm, then you need to get a heater.

The heaters are only best for stabilizing tank temperatures, the tanks that hold 20 gallons of water and below. After all these descriptions, there are different heater types although not all of them functions very well. Some of them doesn’t retain the temperature, others are not durable and whatsoever. To replace these delicate heaters when they fail becomes a bit expensive. You should also be aware that a failed heater is dangerous. If it explodes in water, it may end up exploding the whole tank as well.

Among those other heaters; Fluval M line heater is one of the best. The heater is of high quality compared to the China made.Fluval M line heater is a 16 point quality standard heater made in Europe. It’s made with a blue indicator which helps you detect when it is heating or not. The heater’s dial is easy to turn and also holds the required temperature better.


Fluval heater comes in various sizes;

  • Up to 15 gallons
  • Up to 30 gallons
  • Up to 45 gallons and
  • Up to 65 gallons


Is the number of watts essential?

The number optimum number of Watts ought to be 3-5 watts per gallon of water. More Watts may be required to keep the water stable if its temperature is very cold.


  • In the case where the size of the heater is small, it causes stressful temperature fluctuations more so doing during the spring and fall.
  • If goldfish in a tank doesn’t require a heater, only at rare cases, what of goldfish living in ponds?
  • Researchers have found out that common goldfish, which are small-bodied are comfortable in cold water, regardless of whether it has ice on its top or not.
  • As soon as water drops below 50°F, the fish becomes dormant, eats less, and also behave in a sluggish manner. Slim-bodied goldfish will still be fine so long as the water doesn’t freeze solid.
  • A deicer is useful where the pond is in danger of freezing solid. It prevents the pond from turning into a block of ice and helps with water oxygenation. Instead of keeping your water warm, the deicer ensures there is a hole in the ice to allow an exchange of water and air. The deicer is affordable and if paired with a thermostat heater, they help to save the electricity. 
  • Fancy goldfish kept in a pond require a heater to keep the water at an efficient temperature, above 50° F and at an optimum of 60° F during the winter season. Heaters help to prevent the fancy goldfish’s health problems in winter times.

Yo may also want to know: Do Gold Fish need an air pump ?