Do You Need A Heater

Do You Need A Heater


Heater or No Heater for Your Fish?

One of the most important considerations in maintaining a healthy aquarium and stable environment is your aquarium’s water temperature. A steady water temperature is a must so your fish are not stressed and susceptible to disease. If you find the aquarium’s water temperature is fluctuating daily by more than a couple of degrees you should consider adding an aquarium heater and thermometer.

Fish cannot regulate their body temperature, they have to rely on the temperature of the water in their tank. So what water temperature is best for your pet? The safe temperature zone should always be determined by the type of fish you have. Goldfish do better in cooler water while cichlids and most other tropical fish require higher temperatures. Freshwater tropical aquariums should be kept at approximately 74 ºF to 80 ºF for optimal fish health while goldfish tend to do better when their aquarium water temperature is between 65ºF and 72ºF. Although tropical fish can survive in water ranging from 65ºF to 84ºF, most tropical fish do best when kept in temperatures around the 74 ºF to 80 ºF mark.

There are a number of easy to use, inexpensive aquarium thermometers to choose from that will help you keep tabs on the water temperature of your fish tank or bowl. Choose one that best suits your aquarium shape and size, such as a Digital Thermometer (stick on), Stainless Steel Thermometer (hang-on tank); Plastic Thermometer (suction cup) or Floating Glass Thermometer (includes suction cup also), all will enable you to monitor water temperature.

Which size heater should you use? For desktop aquariums 5 watts per gallon is recommended, so a 3-gallon aquarium will require a 15 watt heater in order to keep the tank at a steady temperature. Go with a reputable aquarium heater manufacturer such as Tetra that has been in the heater business for decades. You do not want to purchase an low cost, inferior heater that can malfunction, harming your fish.


Goldfish are happiest when their aquarium water temperature is between 65ºF and 72ºF.

If your ambient room temperature remains constant and does not fluctuate there’s a good chance that you may not need to add an aquarium heater. Use an aquarium thermometer to monitor tank temperature. If you see that the water temperature is bouncing up and down then add a small heater to keep the temperature steady at the same temperature.

Coldwater Fish

There are several different species of fish that qualify as cold-water fish and tend to do better in colder water temperatures. Goldfish are included in this category. A lot of true cold water fish cannot tolerate the warm water that we generally keep tropical fish in. A water temperature between 65ºF and 72ºF provides an optimum environment for these fish.

Tropical Fish

Tropical fish are most healthy in the range of 74 ºF to 80°F. Some tropical fish may need to be kept cooler while some may need a warmer temperature. Check with your local aquarium store or online for the temperature requirements that best suit your fish.

Betta Fish

If you own a Betta fish, you might be wondering if you need an aquarium heater. The answer is yes, Bettas are tropical fish that prefer warm water ideally between 74 ºF to 80°F.