10 FAQs about Lighting and Heaters in Fish Tanks and Aquariums (Experts Ans., Guide & More)

You’ll agree with us when we say that buying lighting and heaters for your fish tanks can be just as stressful as buying the fish.

Keeping this in mind, we tested out several equipment to bring you answers to some of the most commonly asked questions people have about lighting and heaters. 

By the end of today’s post, you’ll be able to confidently judge what lighting and heating equipment is ideal for you.

10 FAQs about Lighting and Heaters in Fish Tanks and Aquariums (Experts Ans.)

1. What Lights are best suited for me if I have Aquarium Plants in their Growth Phase? 

If you have youngling fish in which you want to stimulate growth, you might want to invest in LED Lighting for your aquarium. 

Using a hanging LED system or a clip-on system is a very easy way to make your small fish thrive. LEDs are a variety of lighting that mimics sunlight very well without causing an excessive amount of algae.

2. When should I turn off my Aquarium Lights? 

That completely depends on the type of fish and plants you have. This is why we prefer that you fish and aquarium plants that belong to the same region. 

European fish normally require about 8 hours of moderate light every day whereas African fish require 12 hours of strong light. 

You need to research the amount of light your fish require and make sure they’re getting the appropriate amount each day. 

Never leave your aquarium lights on indefinitely. This will cause your fish to become stressed and make them more susceptible to diseases.

3. I have LED Aquarium Lights. How high should I hang them above my Fish Tank? 

You can’t really go wrong no matter what height you choose but we’ll generally advise you to hang them about 3-4 inches above your fish tank. This is true for both clip-on and hanging type systems. 

You can use two LED strips or one large one in the middle. Some LED lights also come in larger sizes with a 120-degree profile that covers a very large area and can illuminate your fish tank quite well even from a larger height.

4. Are LED Lights more preferable to Fluorescent Tubes? 

Yes. You should always strive to get LED Lighting for your aquarium instead of fluorescent tubes as the difference between them is astronomical. 

Firstly, LED lights mimic sunlight much better than fluorescent tubes and thus, they can help your plants grow much more quickly than fluorescent tubes ever could. 

Secondly, LED lights are more environment-friendly. The last for a much longer time and consume a lot less energy. 

LED lights are programmable and this allows you to set their warmth and color according to your liking so you can choose the ideal settings that bring out the colors in your fish. 

5. How much Light do I require for my Planted Tank? 

As mentioned above as well, the amount of light depends highly on the type of fish and plants you have in your fish tank.  

Most common fish tanks range from between 20 and 75 gallons and usually, aquariums as large as these require about 2 WPF (Watts per Gallon) of light.

6. Where should I place my Heater on my Fish Tank? 

Your heater should be mounted on your aquarium near the location where your fish tank filter or any other slow water-flow source is. 

Make sure to place your heater in a way that the clean water being pushed into the aquarium by your fish tank filter is being heated up. This will cause an even distribution of heat throughout your fish tank, making for a consistent temperature throughout it. 

7. Is it a good idea to have two Heaters

This is generally not needed unless you live in an extremely cold area. You might need to heaters if just one heater is not effective enough in heating your entire fish tank. 

If you’re worried about your individual heater failing or breaking down then you might also want to invest in a second one that could be used as a backup in this case. 

8. How often should I inspect my Heater? 

It’s very important to inspect your heater daily in order to make sure it’s not malfunctioning. Water temperature is something that both fish and aquarium plants are very sensitive to and a drastic change in this factor can result in catastrophic consequences. In extreme cases, your fish may even die. 

Hence, it’s important that you perform daily checks to make sure your heater is working properly. We recommend adding a separate thermometer (even if you’re heater comes with one) and placing it as far away as you can from your heater in your fish tank. 

9. What size Heater should I buy? 

When we talk about heater “size”, we are not referring to the actual physical size of the heater but rather, we are talking about it’s operating power or wattage or ability to heat an aquarium of a certain water volume. 

As you can probably tell, the size of the heater you should buy depends completely upon the size of your aquarium and the amount of water it holds. 

The golden rule when it comes to size selection for fish tank heaters is that you should have a heater that works somewhere between 3-5 watts per gallon.

For example, if you have a 20-gallon aquarium, you should invest in a heater whose minimum operating capacity is 60 watts. 

10 FAQs about Lighting and Heaters in Fish Tanks and Aquariums (Experts Ans.)

10. What Temperature should I set my Fish Tank Heater to be at? 

If you’ve bought a heater, this must mean that you have tropical fish which require the water temperature to be maintained at a certain level. 

Most marine and freshwater fish thrive between a temperature of 22 to 30 degrees Celsius (71-86 degrees Fahrenheit).

While this temperature is ideal for most fish to live in, we recommend that you do further research into the kind of fish you have and specifically look up what temperature is best for them. 

Having the ideal temperature can sometimes be the key factor that can lead to exponential growth in your fish.


Many people tend to spend all their time and money on fish and fish tanks but then pay no heed when it comes to the research and buying of lighting and heating equipment as their confusing nature can often be a turn-off for them. 

We hope we’ve helped you gain some footing when it comes to getting lights and heaters for your aquarium and we encourage you to spend the proper time in researching what lights and heaters are best suited for your needs. 

Give us feedback and let us know how you got your first lights and heaters for your aquarium.

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