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Aquariums especially planted tanks, take a lot of work. The best way to show off all that hard work is having excellent lighting. Good lighting isn’t just good for visual appeal, either; the plants in your tank depend on it with their life, literally.

LED lights give you the best of both worlds, and then some. Not only are LED lights super environmentally friendly and cost-effective, but they provide all the nutrition your plants need and give your tank a wonderful look only attained by a properly lit aquarium.

However, it’s often not as simple as merely “plug and play”. There are some tricks to properly use LED lights in your aquariums that may not be readily apparent, which we will discuss in this article.

1. Look at the Lights In-Person Before Buying

It might be tempting to buy an LED light from the effects it has on a tank in a photo or video you see, but the color of most single-color LED lights will look different in person. The last thing you want is to buy a light and have it make your plants look awesome, but make everything else look yellow.

The best solution to this is to do your due diligence. If you see a light you like online, try to find a pet store or aquatic store nearby with it in stock and try to see how it looks in person.

One of the exceptions to this is with RGB (Red Green Blue, so named for the LEDs’ ability to produce any color using a combination of red, green, and blue light) LEDs. While RGB lights are more expensive, they also can replicate almost any color with surprising accuracy, limiting the need to verify its color accuracy in person.

I will say, though, that I have purchased RGB lights before that have a yellowish tint to the white light, so even RGB lights are not immune to color tint differences.

2. Only Have the Lights On For 7-8 Hours a Day

One of the major controversial topics in the aquatic hobbyist world is how long the lights should be on in your tank. Some hobbyists say 10 to 12 hours a day is fine, while some say eight to nine hours with an hour break in the middle, known as “siesta-ing”.

We agree with YouTube channel GreenAqua in saying that your lights should only be on in a planted tank for seven hours a day, eight hours max. This amount of time will give the plants and fish all the nutrients they need from the light while preventing algae growth. You can learn more about this in the wonderfully informative video below by GreenAqua.

However, if you don’t have a planted tank, and only have fish in your tank, then you can have the light on for longer. Do not exceed above ten hours of light exposure, as this can incite unwanted algae growth.

3. Do NOT Make DIY LED Lights For a Planted Tank

Lots of people have gotten into the DIY craze lately. It can be so fun to make something yourself instead of just going to a store and buying it.

However, planted tanks are very delicate ecosystems, and the plants need more than just light. Not just any light source will do in a planted tank, and that includes LEDs.

Plants depend on light that gives off Photosynthetic Active Radiation (PAR). The light that doesn’t give off enough PAR will not provide adequate photosynthetic nutrition for your plants, and they will suffer and even die. GreenAqua goes into more depth about this topic in the video below under the heading: “Get the Right Size LEDs for Your Tank and Setup“.

Just like the last guideline, if you have purely fish in your tank and don’t have live plants, it is much more possible to have a DIY LED lighting solution for your tank.

Fish aren’t nearly as light-dependent as your plants. Though, do keep in mind that while they aren’t near as light-dependent as plants, they are still light-dependent and some fish require certain kinds of light, so be sure to research the needs of your fish before attempting any DIY light solutions.

4. Make Sure the LEDs Have Proper Ventilation

Like most light sources, LEDs produce light with heat being produced as a by-product. Most other conventional aquarium light sources produce heat downwards towards the tank. LEDs, on the other hand, produce that heat upwards, towards the ceiling.

One of the best qualities of LED lights is their longevity. LED lights can last for years; sometimes even up to six or seven years! If you have placed the LEDs in a hood or have somehow blocked the top of the LEDs, that heat could get trapped and start to artificially wear down the components and cause them to wear out faster.

An easy solution for this is to simply drill some ventilation holes in the top of the hood to let the hot air get out. Most LED aquarium light solutions will simply need circulating air above them to keep them in good condition, so let the top of your light solution have access to the air to best dissipate the heat.

5. Know the Needs of Your Fish and Plants

Not all fish and plants are equal. Some fish like brighter lights, some like dimmer lights. Likewise, some plants have different needs when it comes to lights.


Make sure you have done research into the needs of your specific fish and plants so you know how much light they need.

If you have fish that like bright lights and fish that like dimmer lights, try to have some good hides and shaded areas in your tank for the fish that like the dimmer lights to hide in and relax away from the brighter lights.

6. Find the Color that Works Best, and Stick With It

One of the big benefits of LED lights is that LEDs are RGB, which means that they can display almost any color you could possibly want. While most beginner setups don’t allow you to control the color of the LEDs, especially with ADA’s lights, many of the more expensive lights do.

However, as Uncle Ben says in Spiderman:

With great power comes great responsibility.

-Uncle Ben

The power to control and change the colors of your lights can be a very tempting thing. But let me tell you, your fish and plants are not near as interested in attending a rave party as you are when it comes to you putting one on for them.

Fish can get stressed out with flickering lights and rapidly changing colors.

Additionally, your plants don’t do well if the light they were just getting used to sudden changes on them; especially if the light doesn’t provide as good of nutrition for them.

Find the color that works best for your plants, and your eyes, and stick with it.

7. Get the Right Size LEDs for Your Tank and Setup

While this may seem like an obvious thing, you’d be surprised by how easy it is to get an LED setup that’s too big or too bright for your tank. Just because a light looks like it is the same size as your tank does not mean that it is the right size of light for your tank, especially when it comes to LEDs.

In the video below by GreenAqua, they talk a lot about how to choose the right size and kind of LEDs that you would need for your tank.

Additionally, they go more in-depth on some of the topics we’ve covered so far, including why making your own DIY LED light solution is an awful idea for a planted tank unless you are a total professional.

Also, if your lights are too bright and you don’t have a CO2 setup in your planted tank, you will have lots of algal growth in your tank.

Nobody wants algal growth in their tank. Algal growth caused by bright light can be remedied by having a CO2 setup, but for beginners, a CO2 setup is expensive and can be quite complicated.

8. Keep the Plant Growth in Check

Another benefit given by LED lights is the effect they have on your plants. LED lights will cause your plants to grow really well, sometimes too well.

It can be really exciting to watch your plants shoot up and grow like they had been given steroids, especially if you not only have LED lights but a CO2 system.

However, just make sure to trim the plants to keep them in check.

Overgrown plants can make a tank look poorly maintained; and seeing as how planted tanks take so long to properly set up and get the plants acclimatized, who wants all their hard work to look poorly done because the plants grew quickly and weren’t maintained.

One of the only differences between aquascaping and landscaping is whether it is being done under or above water, so treat your aquascapes like a gardener would his landscapes.

I hope this post was illuminating for you. LED lights can add a wonderful effect on your tank(s) and are a marvelous invention. Hopefully using LED lights seems a little less daunting now.

If you like the article above, here are some other similar articles you should check out!

Finnex Planted 24/7 fully Automated Aquarium LED light review

Current USA Satellite LED light review

Best LED Aquarium Lighting – reviews & buyer’s guide

Best LED lighting for 125-150 Gallon Aquarium


Hi, my name is Jordan. I've been in the fishkeeping hobby since my childhood. Welcome to my blog where I help fishkeepers enjoy the hobby by offering free guides, advice, & product reviews. Read more...