Despite their seeming ease, goldfish may be a real challenge to care for. Everybody has seen a Goldfish dish or outdoor pond that wasn’t kept warm. But what about your Goldfish—do you really need to warm up your adorable Moor or Shubunkin?
Goldfish, cold-water fish, can endure temperatures from the upper 50s to the mid-70s Fahrenheit. They prefer 62°F to 72°F (17°C to 22°C). In a stable room, they don’t need a tank heater.
However, a heater may be useful. Fancy goldfish are cold-sensitive and may benefit from slightly warmer water. Rapid temperature fluctuations can stress goldfish. A thermostatic heater may assist maintain room temperature if you live in an area where the temperature drops overnight.
Cold water makes goldfish more prone to illnesses. If the tank has a disease epidemic, you may wish to use a heater to raise the temperature to enhance the goldfish’s immune system.
If you use a heater, be sure to check the water temperature to prevent overheating, which is just as dangerous as too-cold temps. Aquarium thermometers are essential.
Do Goldfish Need a Heater? The most complete answer?
The truth, it seems, lies somewhere between yes and no. There are a few important variables to consider:
What Kind of Goldfish Do You Have?
You may be surprised to learn that the cold tolerance of Goldfish varies greatly depending on the species. Dozens, if not hundreds, of distinct Goldfish species exist.
The Black Moor, Shubunkin, Oranda, and feeder Goldfish are all variations of the tiny carp Carassius auratus, native to East Asia. Since their needs are so similar, they may easily mate with one another.
Goldfish are all temperate fish that can survive without a heater, unlike tropical fish like Discus. However, unlike their forebears, Fancy Goldfish are often unable to withstand extreme temperature changes, and nearly never survive temperatures below freezing.
In order to maintain a consistent environment for your Fancy Goldfish, a heater may be necessary. Still, you shouldn’t allow the water temperature to rise over 75 degrees Fahrenheit; in fact, 68 to 72 degrees Fahrenheit is best for them and their less gentle-bred relatives.
Even Fancy Goldfish may not need a heater if your house maintains a steady, moderate temperature. However, I advise having a heater if the temperature tends to drop below this since it will prevent the water from being too frigid.
Given the possibilities available, it might be difficult to choose a dependable heater when shopping. If you’re looking for help finding the right aquarium heater, I hope you’ll check out the one I wrote.
In what kind of surroundings did they grow up?
For decades, dedicated aquarium keepers have successfully bred exotic goldfish species including the Telescope Eye and Black Moor. Many are even reared in the tropics, in the same water as Livebearers Tetras and other species more often associated with the ocean.
Don’t throw your Goldfish into an unheated tank or pond cold turkey if you know they were nurtured in a warm, calm environment. Allow them some time to adapt by gradually decreasing the temperature over the course of a few days.
Keeping Fancy Goldfish below 60 degrees Fahrenheit is not recommended, particularly for larger adults that have been used to warm tanks their whole lives.
The Different Kinds of Goldfish That Need a Heater
- Mirror Telescope
- Puffy Eyes
- Most other Fancy Breeds
Types of cold-tolerant goldfish:
- Japanese Wakin
- Other breeds closer to Wild-type
Fish tanks and patio heaters
Goldfish kept in ponds have unique requirements. We will presume that your Goldfish can survive at least summer temperatures since most outdoor ponds (apart from container ponds) are simply too big to be heated properly.
If the pond freezes over because it is too shallow, you will need to move them inside for the winter. Goldfish may hibernate during the winter in most temperate regions if the deepest part of their pond is at least 3 to 4 feet.
Goldfish and Koi, as I said before, are cold-water fish. Winters in China and Japan are notoriously cold. Your fish should survive the winter without a hitch if you leave an opening in the ice to allow for oxygen and carbon dioxide exchange.
A pond warmer is useful for this purpose. Keeping a hole open in the ice using an electric heater, or “de-icer,” prevents your Goldfish from suffocating.
If you’re wondering “But why don’t wild fish need a hole in the ice?” you’re not alone. The obvious response is that natural water features are far bigger than a typical home pond.
The population density is likewise much lower there. This means that natural ponds have enough oxygen to sustain their animal population throughout the winter. But you’re needed at a man-made pond with far more fish.
Both too hot or too cold?
What temperature thresholds should Goldfish be kept at? It turns out that fish react dramatically to changes in water temperature. Most fish, in contrast to humans, are ectothermic (cold-blooded).
This implies that their core temperature is determined by their surroundings rather than their own actions. Their metabolism slows down when the temperature drops. Most goldfish are cold-water fish that will continue to slow down until the water temperature reaches around 40 to 42 degrees Fahrenheit.
After this, they enter a state of torpor similar to hibernation. They’re still alive, but they’re scarcely moving, resting on the ground till Spring comes around again.
Increasing the temperature, especially over 75–80 degrees Fahrenheit, has the opposite effect and may even be hazardous. Your Goldfish’s metabolism will speed up as the temperature rises. It’s essential that they up their caloric intake, increase their waste output, and speed up their development.
Also, bacteria in tropical environments make quick work of decaying leftovers and garbage. Warmer temperatures accelerate the accumulation of ammonia, nitrite, and nitrate, which may cause ammonia burns and other problems with the water supply.
If the water in your Goldfish bowl or aquarium is on the warmer side, a filter is even more crucial.
Sudden change in temperature
A Goldfish bowl warmer, pond heater, or aquarium heater is a great investment if you live in a climate with extreme temperature swings. As the sun moves across the sky as the seasons change, so do the temperatures.
Extreme changes are jarring because their metabolisms must speed up or slow down to adjust to the new temperature. Goldfish are especially susceptible to opportunistic infections like Ich and Fin Rot when temperatures suddenly rise or fall. Especially if they aren’t exactly living in pristine circumstances.
They may also have trouble digesting when the temperature suddenly changes. The rapid drop in temperature might prevent your Goldfish from digesting its meal in time. As the meal ferments in the intestines, it causes gas and bloating, which may be dangerous.
If a goldfish pond is located in a sunny area, the water temperature might fluctuate significantly. When the sun peaks over a fence or roof around midday, it may rapidly heat the water in a tiny container pond to an unsafe level. Also, once the sun goes down, the temperature drops rapidly, which might be stressful for your fish.
Do Goldfish Need a Heater FAQs
Do goldfish like heated water?
What temperature should goldfish water be? A tank water temperature of between 20°C – 23°C (68 °F – 74°F) is an ideal temperature for goldfish. This temperature will be high enough to encourage strong growth, but without being so high that your fish become stressed by hot water and low oxygen levels.
Can goldfish live in unheated tanks?
Goldfish: Goldfish are the most commonly kept fish in an unheated tank. They come from cooler waters in Asia which makes them excellent candidates for unheated tanks.
Can goldfish live in cold water?
Goldfish are true coldwater fish, as they can withstand freezing cold temperatures and are able to hibernate during winter. They have specifically evolved against a cold climate and so are perfectly capable of living in a cold tank or in your outdoor pond year-round.
Do goldfish like hot or cold?
Goldfish Water Requirements. Considered cold-water fish, goldfish can also be kept in heated aquariums. The optimum temperature for fancy goldfish is 68° to 74° F, while comets and shubunkins should be kept between 60° and 70°F.
Do goldfish need an air pump?
The answer is yes. If any of the following is true then you should add an air pump to make absolutely sure that your fish has enough oxygen: 1) Your water appears very still and your filter isn’t causing much surface movement (you may also want to check that your filter is big enough for your tank!)
Can I keep fish without a heater?
21 Best Cold Water Fish For Aquarium – No Heater Required
Yes, you can have a fish tank without a heater! Provided that you use cold water fish species that thrive in the 50–70 °F temperature range, your natural room temperature will be fine.
Finally, while a heater may not always be necessary for goldfish, there are other aspects of goldfish care that are essential. These include providing a suitably large tank (goldfish require more space than many people realize because they produce a significant amount of waste), a good filtration system, and a diet that meets their nutritional needs. Regular water changes and water quality monitoring are also important to keep goldfish healthy.
Goldfish do not inherently need a heater, but one might be used as a tool to create more stable and ideal conditions depending on the circumstances. In the colder months, heaters may keep the water from freezing over completely. You should really consider getting a heater for your fish if you live in a cold climate. well worth a look!