Goldfish can live in cold water. They live in ponds, streams, and rivers in places with a temperate or tropical climate. Although goldfish live in cold water and need lower temperatures than tropical fish, they cannot live in very cold water. The ideal temperature for goldfish is 65°F to 72°F.
At low temperatures, goldfish’s metabolism slows down, and they become sluggish. Although goldfish adapt to very cold conditions by hibernating in a cold climate, they may perish if exposed to very low temperatures for long durations. To understand how goldfish are affected by temperature, we should first look at how these creatures live in their natural habitat.
Goldfish In The Wild – Natural Water Conditions
Goldfish are descendants of the carp. Carp are hardy freshwater fish that adapt to most environments.
So, the habitat and water needs of the goldfish are like the carp.
Both the carp and goldfish exist in water with cooler temperatures than what tropical fish need.
The ideal temperature for their survival is between 65°F and 72°F.
Although they adapt to a wide range of temperatures, frequent temperature fluctuations affect their well-being.
In the wild, goldfish are at the mercy of nature.
Since they do not live in a controlled environment, they have developed adaptations to survive weather changes.
During the cold months, goldfish will hibernate to stay alive.
During hibernation, goldfish do not need food, and their activity levels reduce drastically.
It allows the goldfish to tolerate the extreme temperature.
Some people have even noticed that goldfish in frozen ponds bounce back to life when winter is over.
Nevertheless, extremely low temperatures are dangerous for goldfish.
Unhealthy fish may not withstand the harsh conditions and may perish. So, it is not advisable to keep these fish in icy water.
What Happens To Goldfish At Low Temperatures? Behavioral Changes, Metabolism, And Hibernation
Whether your goldfish live in an indoor aquarium or outdoor pond, they will show similar behavior when exposed to very low temperatures.
In outdoor settings, the fish prepare for a harsh winter by reducing their intake of food in the months leading up to it.
As the temperature drops, their metabolic activity also reduces. They become sluggish and slow.
So, your once active goldfish will suddenly appear to be lethargic.
When the temperature falls below 50°F, goldfish completely stop eating food.
It will hover at the bottom of the pond and show little to no activity. This stage is called hibernation.
By minimizing activity, goldfish conserve their food reserves.
It keeps them going until the weather improves and is favorable for them to find food.
Hibernation usually lasts for six to ten weeks. The fish will not be able to survive for more than this duration without food.
Ideal Water Conditions For Goldfish Kept As Pets
Both too warm and too cold water is unsuitable for goldfish.
Goldfish owners should ensure optimal living conditions for their pets by controlling the water temperature.
Try to keep the water in the tank within the optimal temperature range to keep your pet healthy.
Indoor aquariums do not need heaters as the water temperature will be within the suggested range in normal conditions.
However, ensure that the aquarium is not prone to cold drafts or winds.
If you keep your goldfish tank outdoors, you may have to use a heater if it gets too cold at certain times of the year.
Use a thermometer to monitor the temperature of the water in their enclosure and find out when it becomes too low.
You can use a heater to restore the temperature to the optimal range in such conditions.
Goldfish kept in captivity will show the tendency to hibernate when the temperature drops.
However, it is dangerous as the conditions are different from when they are in the wild.
Your pet may starve if left unmonitored and even die.
The only exception is when you keep your goldfish outdoors in a pond.
Let us look at what happens to pond goldfish in cold water.
Can Pond Goldfish Be Kept In Cold Water?
Goldfish in outdoor ponds generally enjoy a better quality of life than those placed in aquariums.
They have plenty of space to swim around, and their environment will be as close as possible to a natural habitat.
So, pond goldfish can also tolerate changes like cold weather better than those placed in small indoor enclosures.
Some goldfish owners allow their pond goldfish to hibernate in winter. However, this should be done diligently.
If you intend to make your pond goldfish hibernate, prepare in advance.
Even a thin layer of ice on the pond can be dangerous to your fish as it will reduce access to oxygen.
The harmful gases that will be trapped inside will further suffocate your fish.
To keep your fish safe, ensure that they have access to oxygen even if the water freezes.
Use an air stone for this purpose. Also, monitor the fish regularly so that signs of distress do not go unnoticed.
Changing The Temperature Of Aquarium Water For Goldfish
There is rarely any need to change the temperature of aquarium water for goldfish.
Unless the water temperature falls very low, your fish will be just fine.
Nonetheless, some fish hobbyists change the temperature of goldfish aquarium water for breeding purposes.
In the wild, the fish breed in the warm spring when temperatures rise after winter.
Breeding is induced in tanks by fish hobbyists by replicating the same conditions as in nature.
The change in environmental temperature will trigger breeding instincts in the fish.
Related Question
Can goldfish live in warm water? The optimal temperature for goldfish is 65°F to 72°F. They can comfortably survive in water at room temperature. Although the fish can adapt to slightly higher temperatures, it is not optimal for their survival. There is less oxygen in water at high temperatures, which can suffocate goldfish. The metabolism also increases with temperature, and goldfish tend to have higher activity levels at increased temperatures. As a result, the fish will be under high stress and can go into temperature shock.
