Aqualife Beauty

Aquatic Life Beauty



Does a goldfish need aquarium heater

Does a goldfish aquarium need a heater is mostly a common concern with beginner aquarists who “feel” for their goldfish pets especially when they imagine of extreme drop in temperatures. Their biggest worry is, what is the ideal goldfish water temperature?

Basically, why it’s a concern is because most don’t know that goldfish belong in the hardy cold-water fish carp family. They can comfortably live and thrive in chilly waters. It‘s no wonder that goldfish is a favorite choice for many aquarists.

However, not all goldfishes do well in low temperature waters outside optimally ideal temperature ranges of 62°F – 72°F. This is particularly by the fancy goldfish, famed for their uniqueness in their diversity of colors, shapes and even fin types. Worry not though; as you read on, you’ll get to know, do fancy fancy goldfish need a heater?

As a result of exploratory cross breeding overtime, they’ve increased in number. Above all though, it’s important to note that they don’t survive in extremely low temperatures. Their ideal temperature range is 68°F – 74°F.

Therefore, if the aquarium isn’t in a good climate controlled or well insulated area; you’ll most definitely need a heater to maintain constant temperatures if they fall below the range. Ideally, you’ll need to maintain the right aquarium temperature for goldfish.

The ideal temperature for goldfish water; justification for, does a goldfish aquarium need a heater?

The most ideal goldfish tank temperature ranges between 62°F and 72°F. In simple terms, it should more or less mirrors the normal room temperature or slightly lower. However, should they drop towards 60°F and further, they suffer lethargy and decreased feeding.

In extensive temperature drop, say to 55°F and below, your goldfish will hibernate to floor of the tank. Unfortunately, unlike common goldfish, your fancy goldfish will definitely not survive such punishing low temperatures. This makes it absolutely necessary for fancy goldfish water temperature to be raised a bit. As a result, you’ll thus need to have a heater in tank.

Why your goldfish aquarium should have the optimal temperature range:

While common slim bodied goldfishes can still safely cope even in near freezing waters, to the contrary, fancy goldfish can’t. They’ll will demand of you a heater to maintain the temperatures at the optimal levels of 60°F. This is especially so during winter and spring.

Because extreme temperatures drop signals coming of winter, they stop or reduce feeding and hibernate till winter is over. Therefore, if it’s not winter time and the extreme cold is sustained for long in the aquarium, they’ll still hibernate. Meanwhile, they may starve severe malnutrition or worse and subsequently die.

How to tell the aquarium’s water temperature?

Now then that the answer to; do goldfish need a heater is yes, your next step is to obviously want to know how you’ll accurately read the aquarium’s temperatures at any given time.

Firstly, you don’t have to dip your finger to check because there are better and very accurate thermometers for that. Additionally, besides movable thermometers, some tanks have a built-in with easy to read display digital aquarium thermometer. 

The common thermometer ranges are 50°F – 104°F which provided enough coverage.

Secondly, you have the choice of either a battery or electric powered one. Some brands have additional helpful features like an alarm for notification if the temperatures are out of the set ranges.

Thermometer placements;

They are either:

  • Side tank stick-on thermometers: They are stuck on the outer side of the tank. Their main challenge is accuracy because of external influences to the readings other than by the water temperatures only.

They include and not limited to surrounding lighting including sunlight’s warmth, the heater itself or even the general aquarium’s room temperature.

  • Floating thermometers: All you need is to submerge it wholly and this makes them the popular choice of many. Very easy to use.

Effects of temperature extreme fluctuations in the aquarium life;

Increased temperature rise

Primarily, warm water conditions in the aquariums raises fish’s metabolism. This results in increased feeding rate and subsequently, increased activity in the tank.  However also, the pond’s waters dissolved oxygen (DO) content declines which is definitely not good for the fish.

Because of the increased feeding, fish waste also increases, spoiling the quality of water in the aquarium.

Surprisingly also, moderately warmer waters albeit for a short while (say few days) lowers life expectancy of some parasites and bad bacteria like pseudomonas and aeromonas that afflict your goldfish.

In the contrary, warming also is critical in multiplying the good bacteria although, this you can also do by using eco-balance aquarium supplements easily available in pet stores.

Short stints of a little warmer conditions (particularly when necessary) have been proven to improve response to treatment, hastening recovery from ailments like white spots, red patches on skin and fins.

  • Extreme temperature deep

This has effects both on the plants and the fish in the tank all because of change in water quality.

Because of the semi-dormancy state into that result in aquarium plants during extremely low temperatures, needed oxygen production reduces within the tank as opposed to the levels in warmer water temperatures. However, you can remedy the situation with a good air pump.

Extreme cold’s first effect is on algae which die off. Subsequently, this results to low oxygen levels.

Considering that part of the aquarium’s algae benefits is to clean-off the nitrate and ammonia in the water, its reduction and decay results to excess ammonia dumping in the water. Ammonia majorly affects the fish lungs which is disastrous, especially because immunity is low during hibernation.

Does aquarium heating affect breeding?

Breeding is a good way of increasing your stock of pet fishes. So, if you want to do goldfish breeding within your tank, you have no choice but to create an environment that would mirror their natural habitation.

Out in the wild, at the tail end of winter and on set of spring when the waters warms-up, is when most aquatic lives, goldfish included spawns. This timing is most ideal for androgen, the reproductive hormone production.

Now, the question would be, do goldfish need heaters to breed? And the answer would depend on how cold your tank is. Most importantly, you’ll need to recreate that environment.

So during winter, you may consider raising the temperatures gradually to an ideal level, of say 65°F. However, increase should be in the range of 2°F -3°F each day till the ideal temperature level, which is optimal for laying eggs.

Less cold conditions increase chances of larvae survival in high proportions.

Which fancy goldfishes require aquarium heating?

Virtually all fancy goldfishes will not survive excessively low temperatures which your common tropical fishes would. This is because their immunity is highly compromised which if unmitigated, will ultimately result to death.

Below is a composition of the fancy goldfishes and their preferred temperature levels;

Goldfish typeOptimal preferred temperatures (°F)
Tamasaba, Butterfly, Froghead60 – 70
Lion Heads64 – 72
Fantail goldfish72 – 80
Bubble Eyes70 – 80
Orandas62 – 75
Phoenix goldfish65 – 72

How to care for goldfish in winter: goldfish water temperature in winter and to keep the fish tank warm:

First, the big question is, can goldfish live in cold water? Well, even though goldfishes are hardy and can stay in really cold waters, sudden drop of temperatures is not good. You can use a heater to ensure a gradual drop. This helps with adaptation towards eventual hibernation.

Hibernation is the instinctive response for fish when its winter time or the aquarium gets too cold. Generally, low temperatures reduce their metabolism and subsequently, their feeds intake. Likewise, in winter, and with temperatures falling way below 50°F, feeding stops and dormancy state sets in.

Prior winter adjustments:

Firstly, prior to onset of winter, you may do them good with just a little of overfeeding for a few days to bulk up a bit. It’s also important to be conscious that, as goldfish re-emerges from hibernation; their immunity is low from prolonged starvation. As such, you’re helping them survive for days without food.

Most importantly, when the temperatures plummet critically, they have near nil metabolism activity. So, cut food supply completely, but if you have to, serve very small portions which are low on protein. This helps to reduce pollution of water by waste and uneaten excess feed residues, because of low digestion functioning.

For your family’s coping during winter, you’ll obviously heat your house. As you heat your house, the aquarium waters may also warm-up too to un-ideal levels for your goldfish.

Past 72F°F indoor heating is obviously too hot for the goldfish. This will definitely make your pet fish suffer lethargy and illnesses. To prevent that, you may consider moving your aquarium to a cooler area; say a basement away from indoor heating effects.

Further, because sometimes it can get very cold during winter, pond as well as aquariums can sometimes freeze to blocks. If you allow that to happen, you are no doubt killing your fish because there is extremely diminished oxygen there under.

In that case, you’ll need a deicer to prevent freezing solid and ensuring oxygen level maintenance. Additionally, if your fish are in a pond whose top layer is icing, then, just drill trough an opening to help aeration and oxygen supply to the pond.

Moreover, it’s important to note that deicers are only meant to prevent tank/pond freezing only and not for heating.

Setting up a heater in your goldfish aquarium;

Fish safety should be the primary consideration in setting up a heater besides ensuring that its placement doesn’t compromise the aquarium’s aesthetics purposes.

Further, you should be at a place that will ensure constant and uniform heating of the tank. What better place to have it than at the water in/out flow? You just need to mount the heater on the wall by the suction cups.

Bigger gallons however may need to be served by at least two heaters to sustain consistent water temperature round the tank.

There are several types of heaters. You make the choice based on cost and personal liking. They include;

  • Submersible heaters: Comes fitted with LED lights to indicate when on, and its heating element encased in a toughened glass/tube. It’s placed under water close to filter’s inlet for easy and uniform water heating.
  • Hanging/Immersion heaters: This for instance come with the starter kit and are a darling of most beginner aquarists. While the element is heating the water from beneath, the heater over hangs the top of the aquarium.

While its efficiency has been faulted, it presents another challenge of having to augment the tank’s formation to accommodate the heater’s design.

  • Filter heater: This is basically a filter with inbuilt heating capability. It performs the dual functions of filtration and heating. To its credit, it enables consistent water temperatures.
  • Substrate heater: Uniquely, it’s a set of wires and elements fixed on the base of the aquarium. Of the options available, it’s certainly the priciest and not too common.

How much of energy should the best aquarium heater consume?

Rationally, if your answer to, “does a goldfish aquarium need a heater?” is yes as is expected (depending on the type of goldfish), then you automatically will think of the energy costs that come with it.

However, keeping your pet safe and comfortable shouldn’t drill a hole in your wallet unnecessarily. As such, your heater of choice should be economical and efficient in terms of power consumption.

In general terms, and not unless your tank’s surrounding environment is extremely cold as to need more power than normal, for an actual gallon of water, your average aquarium heater power consumption shouldn’t exceed 5 watts.   

Further, should you be using multiple heaters, their combined power usage shouldn’t surpass the average usage stated above. This is because; water volume is the basic unit of measure (measured in gallons).

A thermostatic heater will help manage your power costs in that it will only come on only when the temperatures fall below the preset range limits. Most importantly, ensure the heater is the right size or a higher size if you please for your aquarium’s size.

How to know the right size of an aquarium heater;

Besides answering; does a goldfish aquarium need a heater question, the next should be, what is the right heater size? There are three critical determinants in deciding the right size of an aquarium heater for your fish pets. These are;

  1. Size of the tank. This is guided by the expected volume of water to be held in the tank,
  2. The level of the water’s temperature projected to be maintained,
  3. What is the temperature of the environment of your tank’s location?

Therefore, in deciding the approximate heating required (measured in degrees), you mathematically less (minus) the average room temperature from the maximum projected aquarium heat.


Maximum projected aquarium temperature (°F)    = 78°F

Tank’s average room temperature (°F)                      = 60°F

Projected heating required (°F)                                  = 18 °F


The illustration above assumes a 5 gallon aquarium.

To avoid speculating and erring when acquiring an aquarium heater, there is reliable and accurate heater size guide.  

You are better off erring on the higher side and have a higher size heater than a smaller ineffective one. As such, where the heating requirement is in between levels and thus no precisely matching heating a heater size, rule of thumb is, pick the next higher sized one. 

Tank Size (Gallons)Projected heating requirement 5°C/9°FProjected heating requirement 10°C /18°FProjected heating requirement 15°C /27 °F
525 W50 W75 W
1050 W75 W75 W
2050 W75 W150 W
2575 W100 W200 W
40100 W150 W300 W
50150 W200 WUse 2, 200 W
65200 W250 WUse 2, 250 W
75250 W300 WUse 2, 300 W

Risks and challenges of using aquarium heaters?

Well, the benefits of using heaters way diminish the significance of risks and challenges thereon. They are;

  • As a challenge, they are pricey gadgets that if you don’t get the right on, you’ll keep hurting your wallet.
  • The malfunctioning may put your pets under stress or worse, at risk of death. This is particularly so if you happen to be away for a while in the hope that all your necessary intervention measures are working. 
  • Heater explosion is perhaps the greatest of the malfunction threats. Explosion of some heaters can potentially poison the water leading to death of pets.

Do goldfish need a heater only? How to heat a fish thank without power;

If the heating required probably doesn’t necessarily need a heater or it could well be that there is an outage, or the heater malfunctions at an inconvenient time, you may turn to these heating means. However, they may not be as effective as a heater;

  • Hot water bottle:

A plastic bottle is most preferred. All you need is to fill it up with hot water and tightly cork it to stop any leaks. Lower it in the tank and ensure that it fits well in your aquarium.

The water will automatically warm up from the bottle’s warmth. It will keep your aquarium at the desired temperature albeit for a while.

  • Use of canopy cover:

In a case of no immediate power back-up, this is mostly effective on a tank already being served by a heater and there is a sudden power outage whose duration may not be predicted.

You cover the tank with a canopy for heat retention and loss prevention from the aquarium. The challenge is that, the cover cuts oxygen supply to the tank from the environment. This can however be overcome by using an air stone and an oxygen pump in the tank.

  • Heating mats:

Of the manual aquarium heating alternatives, heating mats rank highest but for small and easily movable aquariums. Besides their reliability and longevity, they supply instant heat to the tank while retaining the existing tank temperatures.

However, they lack a thermostat and are not ideal for holding high weighed tanks.

  • Aquarium insulation

Insulation can be done with no heat conductor materials like blankets or even papers. They prevent rapid loss of heat as you sort out for aquarium alternative heating.


Naturally, common goldfish are hardy species that can ably withstand a variety of conditions including very low temperatures, both in tank and ponds just as in their natural wild habitation. For these, you may not need a heater even when temperatures plummet.

Fortunately, does a goldfish aquarium need a heater in winter is now well addressed in this article, even if you choose to keep fancy goldfish. You are now well informed of the ideal temperature ranges within which they can survive and which you must ensure to create and maintain. To achieve that, you’ll of necessity, make use of tank heaters.

Can goldfish live in warm water or do goldfish fish need heated water? well, you now have the answer.

%d bloggers like this: