Aquarium plants can thrive in a wide range of lighting conditions from low light to high light, but there are signs that you might need to change the intensity or duration of your lights.
This article will discuss 13 signs of too much light on aquarium plants. That is bad for them and how much light they should have.
We will be also discussing the solution to every sign so, that the signs never come again for you.
- Signs Of Too Much Light On Aquarium Plants
- Leaves Are Turning Brown
- Leaves Are Becoming Yellow
- The Plant Is Overgrown and The Roots Are Dry
- Water Leaves Signs Of a Slimy Coating
- Plant Has an Algae Problem
- Leaves Are Starting To Curl
- The Plant Has Signs Of Brown Edges On Its Leaves
- The Plant Is Not as Green or Growing Excessively
- Plant Is Getting Brown Spots
- Leaves Are Turning Red or Purple
- The Plant Has Signs of Bleaching
- There Are Signs of Root Rot
- The Plant Has Signs Of Leaf Spots
- Can Too Much Light Bad For Aquarium Plants?
- How Long Should Light Be On In a Planted Aquarium?
- Can Aquarium Plants Have Light 24/7?
- Which Color Light Is Best For Aquarium?
- What Is Considered Low Light For Aquarium Plants?
- What Is Considered High Light For Aquarium Plants?
- Our Aquarium Light Recommendation For You
- Are LED Aquarium Lights Good For Plants?
- How To Reduce Light Intensity In Aquarium?
- End Of The Article
Signs Of Too Much Light On Aquarium Plants
Leaves Are Turning Brown
The signs of too much light on aquarium plants are leaves turning brown. Excess light can cause algae to grow inside the tank and fry that lives in the water will not be able to survive because they cannot breathe underwater.
If you have an open-top, it is best to cover the surface with a glass sheet or shade cloth as this will reduce the amount of light entering the aquarium.
Cover the top with a glass sheet or shade cloth to reduce light entering the tank. Below is the one I personally use. You can choose according to the size of the aquarium.
Turn off lights for 12 hours every day; plants need time to rest and cannot be in constant contact with high amounts of light.
Place floating plants near the surface, these will act as natural shades reducing algae growth and providing oxygen for the tank.
Allow light to reach plants for a few hours each day.
Choose low-light-emitting LED lights for aquariums or use fluorescent lamps, this will provide supplementary lighting without harming your aquatic plants too much.
Leaves Are Becoming Yellow
If plants, especially leave, turn yellow they may not be getting enough nitrogen or phosphorus and they could suffer from insufficient levels of potassium. Excess light can also cause leaves to yellow.
This typically occurs when plants are exposed to a sudden change of environment, such as when they’re moved from an office window or porch into the dark confines of your home aquarium.
Leaves may turn yellow due to excess light for about a week after being placed in an aquarium before returning back
Moving plants to shadier spots in your home or office
Lowering the tank light intensity (LED), I will discuss this later in this article.
Turn off lights for a few hours each day, if possible.
Also read: White or blue light for an aquarium? Which works best?
The Plant Is Overgrown and The Roots Are Dry
One sign that a tank has too much light on plants is when they’re completely dried out at both ends, with leaves shriveled up from the heat.
These signs can be seen even in normal lighting conditions for humans – but this will happen faster with more intense light.
One way to protect your tank is by using drip or spray fertilizers with every water change, which will help keep the plant from getting too dried out at both ends of its leaves. Here’s what I use.
Another idea is under-filling your tank so there is more surface area for air to circulate, which will help with the light intensity in your tank.
If you are worried about plants dying from too much light on aquarium plants then consider doing a water change to reduce the number of nutrients in your system!
Plants can’t thrive without these essential minerals so if there is not enough available it could lead to death.
Water Leaves Signs Of a Slimy Coating
This is another sign when the water leaves a sign of a slimy coating on your aquarium plants.
Often when this happens, the signs will worsen as time goes on and it is a sign that there isn’t enough light for the plant to grow normally.
Most of these signs start off with water leaves marks on bulbs or signs that show too much light penetrating into tanks. This can be due to algae growths and signs that show too much light penetrating into tanks.
The best way to make sure this doesn’t happen is by adding more plants and plant lights to the tank.
And the light I recommend you use for the aquarium plant is this one (below). No doubt it also looks cool.
But if signs worsen it can be a sign of an algae bloom which means you should clean your tank right away before the water gets worse.
If not enough signs are taken care of signs, the fish can start getting sick too and it will be a sign that lights need to be turned off at night.
Also read: Should I turn my fish tank light off at night? Is it okay?
Plant Has an Algae Problem
Signs that an aquarium plant has too much light include algae growing out and/or dying. The leaves will also turn a dark brown to black color, potentially even turning into mushy masses by the time it dies from lack of nutrients.
Reduce light intensity – If the signs of too much light are already showing on your aquarium plant, you can reduce the lights by either lowering them or adding a shade screen.
The easiest option is just to lower the tank lighting and turn off any fluorescent tubes that may be in the way. If you’re looking for something stronger, try adding a shade screen. The one I shared above, you can use that too.
This will help redirect all the light back into the water and away from your plants so they can grow properly.
Leaves Are Starting To Curl
It may seem like a good idea to have your lights on 24/24, but under-lighted plants will start showing signs of distress. Leaves are starting to curl and the plant might also grow tall with very few leaves at the top while being spindly in appearance.
Chlorophyll production is decreased which means that nutrients cannot be created and growth will be stunted.
Keep the lights on for 12 hours and off for 12 hours. This will help to reduce signs of too much light on aquarium plants by giving them more time in darkness when they need it most.
The Plant Has Signs Of Brown Edges On Its Leaves
The signs of too much light on aquarium plants could be brown edges on the plant’s leaves or burnt-looking tips.
Brown edges can start to form from removing excess water, as well as not enough CO₂ in the air due to a limited number of bubbles being released.
Reduce the amount of light that is being given to the aquarium plants.
Change the location of your aquarium plants to a darker area.
Increase CO₂ in the air by adding an air stone or diffuser full of bubbles. This will help give more oxygen to the plant as well.
Have a look below that worked great for me. It also keeps the water clean and your fish always active.
The Plant Is Not as Green or Growing Excessively
This is a sign of too much light or not enough CO². Most plants prefer to be in medium-light conditions and will grow the fastest with about two hours per day at full power lighting.
With signs of too much light on aquarium plants, it may require more CO² than usual.
Reduce the power of your lighting. It may require more CO² than usual with signs of too much light on plants.
Try to balance out natural and artificial lighting by adding nighttime periods without lights, or using a lower-wattage bulb for nighttime hours
Add dark-colored substrate such as sand to the aquarium. I use this one.
Add aquatic plants that prefer lower light conditions – such as java moss, Cabomba, and Anubias.
These types of plants grow well with signs of too much light on aquarium plants because they can spread out and escape from intense lighting.
Also read: Do fish need darkness to sleep? Know the fact!
Plant Is Getting Brown Spots
Some signs that the light intensity is too high for aquarium plants are brown spots on leaves. If a plant starts to show signs of stress such as small brown spots.
Then it may be time to reduce or eliminate lighting in your tank because this could lead to the death of some aquatic plants and severely stress out other aquatic plants.
Reduce the intensity of your LEDs.
Turn off lights for a few hours at night.
Install an aquarium cover (discussed above already, how this can help) to block out light from windows or other sources.
Leaves Are Turning Red or Purple
Some signs of too much light on aquarium plants can be leaf color change. Leaves may turn red or purple if there is too high a level of intense light exposure which could cause the chlorophyll to break down, leading to these signs.
It may be necessary to reduce the light intensity in the aquarium.
If it is not possible to change the lighting, select plants that have low requirements for intense light exposure.
This can help signs of too much light on aquarium plants go away while still being able to enjoy this hobby.
The Plant Has Signs of Bleaching
The sign of bleaching in aquarium plants can be a sign of too much light.
In planted aquariums, one can have too much light on the plants if they are constantly exposed to them for long periods.
This is because signs of bleaching in a plant will show signs that there is not enough Chlorophyll or pigments needed by the plant to absorb light and turn it into an energy source.
The solution to reducing signs of bleaching in aquarium plants is to reduce the amount of time that lights are on in a planted aquarium.
LEDs should be switched off at night and only turned on when needed during daylight hours
Leaving LEDs constantly on can also contribute to signs of bleaching because they give out intense light.
Another solution is to change the color of your lighting since some plants will show more signs of bleaching than others.
There Are Signs of Root Rot
The sign that your planted tank has too many hours of artificial lighting is root rot.
This is a condition that will slowly kill your plants and can be prevented by changing the lighting schedule.
The signs of root rot are brown bits at the base of leaves, wilting leaves, and yellowing in between leaf veins with dark green patches on top.
Root rots happen when too many hours of artificial lighting are on too long.
Reduce the amount of light to 12 hours per day.
Leave lights on for only 11 hours a day and turn them off at night.
Change your lighting schedule so that plants get more time in darkness than they do with artificial lights turned on.
The Plant Has Signs Of Leaf Spots
A leaf spot is an infection caused by fungi, bacteria, viruses, or too much light.
The leaves are covered with small brown to black dots that form circular patterns on the surface and in some cases appear as raised lumps.
Leaf spots can be treated easily using copper fungicides like Kocide (copper sulfate) or Ridomil (mancozeb).
Reduce the amount of time there is light in the aquarium.
Try to find a white or blue LED that has less wattage.
Change out all lights for fluorescent bulbs with lower intensity (less than 40 watts).
Can Too Much Light Bad For Aquarium Plants?
Yes, too much light can be bad for aquarium plants. Too little light is better than too much, but it depends on the type of plant and how many hours a day they have been exposed to that amount of light.
Plants need different amounts of heat, nutrient levels, water conditions, etc. All these factors play into what level of lighting is appropriate for them.
Too much light can kill aquarium plants if the intensity of the lights is not reduced or if they stay on 24 hours a day.
This happens because there is no time for photosynthesizing and plant respiration to take place with high levels of light.
Aquarium plants need a range of light intensities, including low and high levels.
They should receive at least 12 hours of bright light per day to maintain their health in an aquarium system that is not planted with any other type of aquatic life.
This time can be split into portions if the lights are left on for less than twelve hours per day.
How Long Should Light Be On In a Planted Aquarium?
For a planted aquarium the best time of day to turn on the lights is from when you start your aquarium maintenance routine until about an hour after sunset.
If the light should be left on all night, plants would eventually experience so much photoperiodism stress that it can cause signs of too much light and lead to injury or death of plants.
Answering the question of how long light is on in a planted aquarium is dependent on the type of plants being used.
Low-light aquariums should have a photoperiod that is less than 12 hours per day, while high-light tanks can experience 24X24 lighting without signs of too much light and be considered to be thriving in this environment.
Can Aquarium Plants Have Light 24/7?
A common question among those new to aquarium plants is whether they can have light 24/seven in their planted tank.
The answer may surprise you but the answer is yes, many aquarium plant species are adapted to grow under bright conditions.
However just because some aquatic plants will be able to live with a lot of light does not mean that it should be provided.
You should be cautious when providing a lot of light because too much can have negative effects on the plant and even cause it to die off.
Which Color Light Is Best For Aquarium?
Now, comparing these three lights I think that the best lights for aquarium plants are LED.
Want to know the reason?
Scroll down (discussed in the other section) the best color light for an aquarium is blue light.
To ensure that the aquarium plants will receive enough blue light.
It is best to use a full spectrum fluorescent bulb or an LED fixture with at least 50% of its output being in the blue range (remember, some LEDs are not made for growing plants).
Aquarium plants need different types of light to thrive, depending on the color range it falls in.
There are three main categories that aquarium plant lighting falls into – full-spectrum (daylight), red and blue LEDs, and white fluorescent bulbs which are the least efficient.
Full Spectrum Light
Full-spectrum light is the type of aquarium lighting that mimics natural sunlight.
It’s best for plants living in shallow water to receive an equal amount of red, blue, and white LED lights so as not to disrupt photosynthesis (plants need all three colors)
These are low-wattage LEDs designed especially for growing plants.
They come in three colors red, blue, and white LEDs. The most efficient are the blue LEDs (they should make up over 50% of output).
White Fluorescent Bulbs
These are also low-wattage bulbs designed for plants, but they only provide a small amount of light in the spectrum that aquarium plants need.
This is the least efficient but often cheapest type of aquarium lighting for plants.
Also, check this out: 7 Ways to reduce the light intensity in the aquarium
What Is Considered Low Light For Aquarium Plants?
Low light for aquarium plants is typically considered anything less than 20w of fluorescent lighting.
LED lights are often on the low end at about 50-150 lumen per watt, but they do have a great intensity that can help with this problem.
Low-light aquarium plants should be able to live near or under the surface and still receive enough radiation for photosynthesis.
This is because low-light plants don’t need as much intensity to grow, so roots can be closer to the surface.
Low Light Aquarium Plants:
- Anubias Nana
- Aponogeton Crispus
- Cryptocoryne Parva
- Echinodorus Tenellus (dwarf)
- Echinodorus parviflorus
- Lemna Minor
- Narrow Leaf Java Fern (Microsorium Pteropus)
- Riccia Fluitans (duckweed)
- Salvinia Minima. Aquatica
- Spirodela polyrhiza
- Vallisneria Spiralis (plant)
- Wisteria Sinensis
What Is Considered High Light For Aquarium Plants?
The high light for aquarium plants is typically considered anything over 20w of fluorescent lighting, with some tanks going up to 200w or more.
LEDs are often on the high end at about 200tw, with some going as high as 400w.
If your tank is well-lit and the plants are still not growing, it may be time to increase lighting intensity or try a different type of light altogether.
- Amazon Sword Plant
- Dwarf Baby Tears
- Anubias Nana
- Java Fern
- Giant Vallisneria
- Hygrophila Difformis
- Water Lettuce
- Cabomba Carpatica
- Hydrocotyle Sibthorpioides
- Dwarf Hairgrass
Our Aquarium Light Recommendation For You
If you are unhappy with the color of your light, there is a wide variety to choose from.
For freshwater plants we recommend using either full spectrum or plant grow lights – these include:
- Full Spectrum
- F40T12/F14T12 Fluorescent
- Plant Grow Lights (20w)
- Plant Grow Lights (100w)
- Plant Grow Lights (150w)
For Saltwater plants, we recommend using either full spectrum or high-output metal halide lights. These include:
- Full Spectrum
- F40T12/F14T12 Fluorescent
- High Output Metal Halide Lights (150w)
- High Output Metal Halide Lights (250w)
- High Output Metal Halide Lights (400w)
- High Output Metal Halide Lights (600w)
Related article: Can aquarium plants grow with led lights?
Are LED Aquarium Lights Good For Plants?
Alternatively, aquarium owners can use LED lights which are the best lights for plants in an aquarium.
This type of bulb more closely replicates sunlight and is easier on plant leaves than other types of bulbs with a softer color temperature like fluorescent lamps or incandescent ones.
LEDs also do not emit as much heat so the water temperature is also unaffected by the light’s heat.
Additionally, LEDs are more durable than other types of bulbs and can last for up to 50% longer before they need to be replaced.
They have a lifespan of about 25,000 hours versus fluorescent lamps which typically only last 12-15 months with an average use time of 15 hours per day.
LED aquarium lights are the best for plants because they emit more natural light and do not produce as much heat. In addition, LEDs last longer than other bulbs making them less expensive to maintain overall.
How To Reduce Light Intensity In Aquarium?
To reduce the light intensity in the aquarium, you can lower the light fixture, or add a filter that blocks out light.
Aquarium plants need varying amounts of lighting depending on their type and how large they are.
The intensity should be between 30 to 150 watts per square foot (w/sq ft) for aquariums with low-light plants like java moss or ludwigia.
Plants like Java fern and anubias require on average 60w/sq ft, while medium-light plants such as rotala or swords need around 100 w/sq ft.
High-intensity lighting is needed for faster-growing plant species like Ludwigia, Bucephalandra, and Bolbitis which thrive between 150w/sq ft and 250 w/sqft.
Light is one of the most important variables for aquarium plants, but it’s also a juggling act between giving them enough light to grow well without overdosing them with energy which will cause algae problems in your tank.
Read our detailed article on how to reduce the light intensity in aquariums. This will not only teach you how to reduce the light intensity in aquariums but also how to make your aquarium plants grow healthier and faster.
End Of The Article
So, finally, signs of too much light on aquarium plants are:
Signs that the plant may be getting fried by all the extra heat and light.
Signs can include yellowing leaves, brown leaf edges, and fronds drooping down instead of standing up straight as they should.
It can also include brown spots or dead areas in a leaf, and brown or yellow patches on the plant.
Signs can also include a significant change in leaf shape and/or coloration from what was observed before the light intensity increased.
So, now you know how too much light is bad for aquarium plants.
Also if you have seen any similar signs in your aquarium plants. Let us know in the comment section below!