The goldfish is one of the most popular fish you can find in an aquarium and is considered a cold water fish. People prefer them because they come in a wide variety of shapes and forms and, most importantly, for the beauty of their vibrant color. They are also fairly small in size, so it is easy for someone to get a goldfish as a pet, as they do not require a very large space.

However, did you know that to maintain your goldfish’s health, you must pay close attention to the temperature of their habitat? Let’s look at the ideal temperature for your goldfish to thrive and, specifically, the best temperature for a goldfish tank.

goldfish in small glass jar

Factors Determining the Temperature of a Gold Fish Tank


There are a lot of factors that can determine what would be the appropriate temperature for your goldfish. One particular factor is what type of goldfish you have. There are two main categories of goldfish: the egg-shaped goldfish and the slim-bodied goldfish. These two categories include several different kinds of goldfish that might require different temperature levels from the others.

Slim-bodied goldfish is the most classic type of goldfish, and it has the look that people associate most with the species. This type of goldfish is considered quite sturdy, meaning they can thrive in various environments with various water conditions and temperatures.

Moreover, they can also live in ponds instead of tanks, allowing them to grow bigger. Slim-bodied goldfish are generally fine living in colder environments, and they can also tolerate warmer water temperatures, as well as frequent temperature fluctuations.

On the other hand, the egg-shaped goldfish is a little more delicate, which has granted them the nickname “fancy goldfish.” They look slightly different from the slim-bodied goldfish, as their physique is more rounded, and they are also double-tailed.

Many people prefer them over the more regular-looking slim-bodied goldfish due to their unique appearance and the complexity of their breeding. For this reason, some egg-shaped goldfish are considered quite rare and thus much more expensive.

However, the biggest disadvantage of the egg-shaped goldfish is also the reason people love them. The unique look of this common goldfish requires more meticulous care, and as mentioned earlier, they are more delicate. This type of goldfish is more prone to diseases, so non-ideal water and temperature conditions in the goldfish aquarium might make your goldfish very ill.

For that reason, it is not recommended to keep such a goldfish in a pond, as a tank, which is a more controlled environment in terms of temperature, would be a much more suitable place for it. Egg-shaped goldfish need to be in generally warmer temperatures, so a tank or goldfish aquarium with a water temperature slightly lower than room temperature might be more suitable.

Habitat & Climate


As mentioned above, there is also a big difference in the temperature found in different habitats. Ponds are usually in an exterior space, so their temperature is based on the weather conditions.

The water temperature could change as quickly as the weather, so there can be a lot of temperature fluctuation within a pond. On the other hand, thanks to the use of an aquarium heater, the tank temperature range in a heated tank is better regulated, creating a controlled and stable environment no matter the climate condition.

While some fish can survive a colder winter climate, not all kinds of goldfish can live in such conditions. Aquarium water that is too warm can also have a similar impact on your goldfish’s health as colder water can.

Fluctuating temperatures or a sudden water change can also severely stress your goldfish, in addition to making it more prone to illness. Therefore, a pond exposed to the elements may not be ideal for all kinds of goldfish.

A tank is often considered an appropriate habitat for many kinds of goldfish due to the temperature regulation that can be achieved thanks to the aquarium heater. Indeed, most fish owners buy aquariums with water heaters since many freshwater fish species are very sensitive to temperature changes.

This is especially true in very cold climates; a fish owner is required to purchase a tank since many freshwater fish cannot withstand too harsh weather conditions and colder temperatures.


You can now understand that water tank temperature is important for many fish species. However, did you know that it also affects their breeding process? Indeed, this is true for the goldfish.

Goldfish owners interested in breeding their pets should know that temperature fluctuation plays a big role in the breeding cycle. Most goldfish tend to lay their eggs during springtime since their offsprings have higher chances of surviving than during the winter.

The increase in water temperature signals a goldfish that it is mating season. Interestingly, male goldfish produce higher amounts of their reproductive hormone during springtime than in winter.

Therefore, if someone is interested in breeding their goldfish in their tank, they must imitate how the weather changes occur in their natural environment. Since most tanks keep a steady temperature all year long, the breeder would have to slowly lower the water temperature and then gradually increase it to induce breeding behaviors in their goldfish.

goldfish in water tank

What Is the Ideal Temperature for Goldfish Tank?

Goldfish are considered ectotherm animals, meaning they cannot regulate their own body temperature and rely on the temperature of their environment, in this case, the water temperature.

Goldfish tend to thrive in medium temperatures between 65 to 72°F (or 18 to 24°C). They tend to prefer warmer water temperatures since they kickstart their metabolism, which increases their growth.

A boost in their metabolism also increases the strength of their immune system, which prevents the contraction of any diseases. For that reason, increasing the water temperature to around 80°F might help a sick goldfish combat its illness.

Moreover, as mentioned above, the rise in temperature from colder to warmer also induces breeding. If the water temperature starts from a lower 54°F and gradually increases to 74°F, your goldfish is expected to start reproducing.

How Can the Wrong Temperature Affect Your Goldfish?

A higher temperature is not always ideal for your goldfish. The increased metabolism makes them eat more and, in turn, produces more waste. If the tank is not properly maintained, the water conditions will worsen, affecting your fish’s health.

An increase in their metabolism can also mean that they will grow faster and, thus, decrease their life expectancy. In nature, goldfish usually hibernate during the cold months by lowering their metabolism. Therefore, steadily increased metabolism will eventually lead them to pass sooner.

Higher temperatures also decrease the amount of oxygen in the water, making it harder for your fish to breathe. Therefore, it is recommended not to raise the water temperature higher than 80°F.

Like high water temperatures, water change and temperature fluctuations can also impact your fish and send them into shock. If adjusting the temperature in your aquarium, you must be very careful since changes of even two degrees can shock your otherwise healthy goldfish. Some symptoms that your goldfish could experience are rapid breathing, lethargy, floating problems, etc.

In addition to the water temperatures, you need to use the right water in your fish tank. Tap water is the most used water in goldfish tanks and is a suitable choice as long as the water is treated with a water conditioner before introducing a new fish or new goldfish tank mate.

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