Aquarium lighting not only helps to showcase the underwater world of your tank; it also influences the health, colour and behaviour of the inhabitants of its inhabitants. This is influenced by how long the lights are kept on, the type of lighting (e.g., fluorescent tube and light emitting diode [LED]), their colours and their quality.
Why Aquarium Lighting Is Important
Aquarium Lighting And Fish Health
Fish rely on consistent lighting to regulate their biological clocks, affecting feeding, movement, and breeding behaviors. As fish don’t have eyelids, they depend on periods of darkness in their environment to be able to rest properly. Prolonged exposure to light can therefore lead to sleep deprivation and reduce the well-being of your fish. Also keep in mind that different species have different lighting preferences. For example, cichlids prefer dimmer environments, while guppies and tetras love a brighter tank. Because of this, it’s important to select a light brightness and timing schedule that is close to their natural environment to keep them as happy as possible.
LED lights are popular due to their energy efficiency, customizable settings and longer life spans. They allow for adjustments in intensity and spectrum, catering to the specific needs of your aquarium inhabitants. Advanced LED lights enable fine-tuning of the light spectrum to match the requirements of fish, plants, or corals, making them more efficient than traditional bulbs.
Aquarium Lights And Aquarium Plants
If you have live plants in your tank, it is also important to select a light that aligns with their needs. Similar to terrestrial plants, aquatic plants require light for photosynthesis, the process by which they convert light into energy. The quality, duration, and intensity of light can all affect their growth and oxygen production. For plants, it’s not just about how long the light is on; live plants also need specific wavelengths to grow and even flower.
What is the Best Light Spectrum for Planted Tanks?
For planted tanks, a full-spectrum light with a mix of red and blue wavelengths is ideal to help plants grow. Red light promotes flowering and fruiting in plants, while blue light encourages healthy growth. Modern LED lights often come with adjustable spectrums to cater to a range of plant needs – look for ‘tropical’, ‘plant’ or ‘full wave length’ options.
How Tank Lighting Affects Algae Growth
Algae, like plants, utilize light for growth. Both excessive and improper lighting can lead to unwanted algae blooms, which often compete with plants for nutrients and can also disrupt the aesthetic of your tank. Incorporating floating plants, such as duckweed or water lettuce, can be a natural and effective way to combat this, by diffusing excessive light and creating shaded areas that inhibit algae growth. These plants also compete for nutrients in the water column like phosphates and nitrates, which are significant contributors to algae blooms.
Optimal Aquarium Lighting Duration
General Lighting Advice for Fish Tanks
For most freshwater aquariums, aim for 8 to 10 hours of light per day. This duration mimics natural daylight cycles and helps maintain a balanced environment. Overexposure to light can lead to stress in fish and promote algae growth, while insufficient light may hinder plant growth and disrupt fish behavior.
The easiest way to maintain a consistent lighting schedule is by using a timer. These don’t have to be anything fancy and can be easily picked up from any hardware store, or online. They sit between the wall socket and the plug for your light, and control the time of day that power is sent through to your light, saving you the job of turning it on and off each day.
Lighting Hours for Planted Aquariums
Planted tanks can require longer lighting periods, typically between 10 to 12 hours daily, to support plant growth. Though this is not set in stone. If opting for higher lighting hours like this, keep an eye on your tank at the start to make sure that it is not encouraging algae growth. It can be a good idea to slowly build up to this target from the standard ~8 hours, to give the plants and fish a chance to acclimate. Remember, not all plants want the same amount of light, with low-, medium- and high-light preference species available. So, do select your plant species and lighting schedule to keep these considerations in mind.
How Much Light Do Shrimp and Other Invertebrates Need?
Invertebrates like shrimp and snails generally prefer dimmer lighting conditions. Aiming for 6 to 8 hours per day is ideal. Because of these lower light level requirements, it can be worth looking for low-light plants to stock your aquarium with, to ensure that they’re compatible for the chosen set up.
If, however, other elements of your tank mean that you are aiming for longer lighting hours than this, I would recommend adding a number of hiding spots and shaded areas to your tank to enable them to move to areas where they feel more comfortable.
Seasonal Adjustments to Tank Lighting
You may wish to take things one step further with the lighting in your tank. Incorporating seasonal variations by slightly adjusting light durations can mimic natural environmental changes. This can benefit certain species’ breeding behaviors and can help with the overall health of your fish. If opting for this approach, do keep in mind that both ambient room light as well as any light from nearby windows can influence this lighting schedule and potentially also contribute to algae growth.
Common Aquarium Lighting Problems
Risks and Signs of Too Much Light in Your Aquarium
Excessive lighting can lead to several issues, including:
Algae Blooms: Overexposure promotes rapid algae growth, which can outcompete plants and reduce oxygen levels. This might build up on structure in your tank, or you might see the water itself getting cloudy and discolored.
Stressed Fish: As mentioned above, continuously bright lighting can stress fish, leading to suppressed immune systems and increase their susceptibility to disease. Some signs of stressed fish include erratic swimming and hiding.
Temperature Fluctuations: Certain lighting types, like fluorescent or halogen bulbs, can increase water temperature, which is particularly risky in smaller tanks with sensitive species. Though this can be offset to some degree if using a heater with a thermistor.
Damage to Live Aquatic Plants: Too much light can lead to yellowing or burning of plant leaves. If this happens in your tank, consider either reducing the intensity of your light (this can also be done by moving it further away from the water level) or reducing the number of hours that it’s on during the day.
How Not Enough Light Affects Your Tank
Insufficient lighting can result in:
Poor Plant Growth: Plants may become weak, lose color, and stalky without adequate light.
Altered Fish Behavior: Fish may become lethargic or exhibit unusual behaviors due to disrupted circadian rhythms.
Algae Issues: While it might seem counterintuitive, too little light can also lead to certain types of algae that thrive in low-light conditions. For example, Black Beard Algae, Green Spot Algae, Brown Algae (Diatoms), Blue-Green Algae (Cyanobacteria), and Fuzz Algae all can appear in low-light conditions. If struggling with excess algae in your tank, see our post on algae eating fish, shrimp and snails for some suggestions on how to naturally combat this issue.
Finding the Perfect Aquarium Lighting Schedule
To summarize, finding the right lighting schedule for your aquarium is about understanding the needs of your fish, plants, and invertebrates that live in that tank. Aim to select species that have similar lighting requirements, and then set up a regular lighting schedule that best reflects this. If you do have a few species that are less fond of the lime light, add some darker areas of the tank to give them spots where they can feel comfortable. And for any lower-light plant consider moving them into shade or further away from tank lighting if they are struggling with the light intensity within your current set up.
To summarize:
Aquarium Lighting Duration: Start with to 8-10 hours of light per day, and gradually adjust up or down based on how your aquarium responds to this.
Aquarium Lighting Intensity: Adjust the brightness based on your tank’s inhabitants and live plants.
Aquarium Lighting Consistency: Use timers to maintain a regular lighting schedule and to avoid overexposure.
