Do Goldfish Need a Heater?

Many goldfish owners are not sure if they want to install a heater in their aquarium. Often, the confusion stems from the fact that goldfish can withstand a wide range of temperatures. Consequently, some people believe that they don’t necessarily need a heater for their goldfish tank.

So, do goldfish need a heater? In theory, goldfish are coldwater fish, meaning a heater isn’t necessary for them. However, experts advise against keeping goldfish in too cold water. So, if your water temperature often falls below 65 degrees Fahrenheit, you probably need a heater to keep the water warm.

Interestingly, different types of goldfish thrive in different water temperatures. So, you may want to know what temperature range is ideal for your specific goldfish breed. In addition, you may have questions regarding how to choose, set up and use a heater the right way. Hopefully, this article will resolve most of your queries. So, keep reading!

What is too cold a temperature for goldfish?

In the wild, goldfish live and thrive in the cold water environment of streams, rivers, and lakes. Not surprisingly, people often see goldfish as a coldwater fish. However, that does not mean they can survive frigid temperatures. In fact, goldfish may begin hibernating and consequently stop eating in freezing cold. Ideally, you should keep your goldfish slightly below the normal room temperature.

In fact, goldfish could go into a state of inactivity when the temperature is too high or too low. Ideally, the water temperate of your goldfish tank should be anywhere between 60 and 65 degrees Fahrenheit. Anything below 60 degrees and your goldfish could become lethargic. It may even stop eating. Also, at temperatures below 50 to 55 degrees, they could start hovering at the bottom of the aquarium. In fact, that could be a sign of hibernation.

What temperature is too high for a goldfish?

Typically, anything above 80 degrees Fahrenheit (or 27°C) is too high for your goldfish. In fact, a high temperature often lowers the oxygen levels in the tank water, resulting in stress to the goldfish. Hence, you should avoid placing your goldfish tank in direct sunlight. In addition, consider using a tank with a large surface area. Just to clarify, oxygen from the air enters the tank water at the surface. So, a large surface area means your tank water would soak in more oxygen. Also, definitely use an air pump in your goldfish aquarium.

Do goldfish behave differently in different water temperatures?

Yes, temperature changes often trigger behavioral changes in goldfish. For instance, your goldfish could become totally inactive in temperatures lower than 50 degrees Fahrenheit. On the other hand, keeping your fish in hot water may make them stressed. Also, when the temperature is above 85 degrees, your fish may start gulping at the surface. That way, they’d try to intake oxygen from the air. Evidently, this means the tank water has low oxygen levels.

Interestingly, if you keep your fish in warm (neither too hot nor too cold) water, it’ll benefit them in many ways. For instance, their digestive and immune systems will improve. Plus, you’ll also notice them swimming faster in warmer water.

How do goldfish tank heaters work?

Simply put, a tank heater works by converting electricity into heat. Interestingly, you don’t need to manually turn the device on and off to maintain the water temperature. Instead, you can simply set a minimum/maximum range. So, when the water temperature goes below the minimum level, the heater will turn on automatically. Similarly, if the temperature rises to the max, the heater will automatically turn itself off.

What is the wattage requirement?

Importantly, your aquarium heater should have the capacity to provide enough wattage for your goldfish tank. However, this also depends on the size of your tank. For instance, a large aquarium with more than 60 gallons will need 3 watts per gallon. On the other hand, small tanks with a capacity of less than 50 gallons often need 5 watts per gallon. Remember, however, that the wattage requirement could vary depending on the environmental temperature. If the room temperature is very low, you may need more watts per gallon of water.

How to choose the right type of aquarium heater

Typically, you’ll find four main types of goldfish tank heaters. Often, the right type for you depends on your individual needs and preferences. For instance, submersible heaters are a great choice for small tanks. You can submerge them fully into the tank water. Hence, all the produced heat will transmit to the water with no losses. Plus, submersible heaters are safer than most other heater types.

In comparison, immersible heaters are more affordable but they don’t sink fully into the water. Instead, only the heating element will remain inside the water. On the other hand, in-line heaters are ideal for large tanks. In this case, the heating element remains outside while the heat passes through a pipe or filter to the inside water. Also, you’ll find other types, such as substrate heaters and in-sump heaters.

What are the different types of aquarium thermometers?

Aquarium thermometers come in different shapes, sizes, and features. Plus, each type has its own pros and cons. So, how would you choose the right type for your goldfish tank? First of all, know that there are mainly three types to choose from. The first type is stick-on LCD thermometers. Often, you’ll fix them at the outside wall of your tank. This, however, means that room temperature could impact the reading of this thermometer.

Thankfully, you can use a digital thermometer to measure temperatures more accurately. However, digital thermometers are more expensive than other types. Often, you need to install the sensor of this thermometer on the inside and the display on the outside. Finally, you can choose to use a floating or standing thermometer. Typically, you’ll place this thermometer inside the tank. They are more affordable but less accurate than their digital counterparts.

Do Oranda goldfish need a heater?

First of all, know that Orandas fall in the category of fancy goldfish. Hence, this big-headed fish is vulnerable to sudden temperature changes. In other words, you must avoid quick temperature fluctuations to keep the fish healthy. To that end, installing a good quality heater is absolutely necessary. Ideally, you should keep an Oranda in a big tank. Also, make sure the water temperature is between 65 and 72 degrees Fahrenheit.

Do guppies need a heater?

Ideally, guppies should be kept between 75 and 80 degrees Fahrenheit. Of course, guppies can withstand a little higher or lower temperature. However, it is always a good idea to keep them within 70 and 85 degrees, at least. In fact, guppies can get certain fish diseases when the temperature is too high or too low. So, make sure you use a heater in your aquarium. However, if you live in tropical areas, you may consider keeping them without a heater. 

Do Betta fish need a heater?

Just like guppies, betta fish are tropical fish and they like warm water. Ideally, you should keep your betta fish in the temperature range of between 78 and 80 degrees. Anything below 68 degrees could make them inactive and sick. Likewise, if the temperature rises above 85 degrees, it could negatively impact the fish’s health. So, investing in a heater is almost necessary.

Do fantail goldfish need a heater?

Often, fantail goldfish are a favorite of first-time pet owners, thanks to their colorful look and double-tail fins. However, they are a fancy breed and extremely sensitive to temperature fluctuations. In general, fantail goldfish thrive in slightly cold water. So, try to keep the water temperature between 70 and 75 degrees. Importantly, the water temperature should not go over 85 degrees. Otherwise, your fantail fish could get stressed and eventually die. Also, add an air pump to your aquarium to help keep the oxygen level high.

How to keep your goldfish aquarium warm during a power outage

Unfortunately, power outages are the bane of most aquarium owners’ life. Not to mention, the consequences of a long power cut could be devastating. For instance, once your air pump goes out of power, the tank’s oxygen level could decrease. Meanwhile, your heater will stop working. As a result, keeping the tank water warm could be a challenge. Thankfully, there are steps you can take to slow down the temperature loss. For instance, you can close the lid of your goldfish tank. In addition, consider wrapping the goldfish tank with a blanket or towel. If your room has a wooden fireplace, use it to maintain the room temperature. That way, you can make it easy for you to keep the aquarium warm for some time.

How to know if the aquarium heater is broken?

First of all, turn your heater on. Secondly, check if the light of the heater is on or not. However, just because the light is on doesn’t mean it is working. For instance, you may notice no change in the water temperature even when the light is on. So, the next step is to check if the temperature is changing. To that end, first, check the water temperature before turning on the heater. Next, turn on the heater and recheck the temperature and see if there is a change in the temperature. if not, then maybe your aquarium heater is broken.