Is light needed in the aquarium? Creating ideal conditions for fish and plants

If you are thinking about buying an aquarium or have just set one up, the question of lighting has probably crossed your mind. On the one hand, it is difficult to see the inhabitants without a lamp, but on the other hand, will constant lighting harm them? This is a valid and important question because light in an aquarium is not just decoration, but one of the key factors in the health of your entire small ecosystem.

For fish, light primarily sets the natural rhythm of life, imitating the change of day and night. This helps them feel calm, reduces stress, and regulates their behavior. But for living plants, lighting is literally a matter of life and death. Without light, they cannot grow, absorb harmful substances, or oxygenate the water.

However, simply screwing in any light bulb and leaving it on is a bad idea. Too bright or too long light exposure can lead to an algae bloom, which will turn the water into a murky green liquid. The ideal balance is the right power, the right spectrum, and a clear lighting schedule, usually around 8-10 hours a day. Let's figure out how to create such a balance so that the fish are comfortable and the plants delight the eye with their lush greenery.

Is lighting necessary in an aquarium with fish?

Undoubtedly, if the owner wants to enjoy the aesthetic appearance of the fish in the aquarium, they will definitely need light. Some fish species, such as goldfish, can fade in color if there is not enough light.

Moreover, fish need light to feed and engage in other fish activities. But they also need a few hours of darkness to relax and rest.

It is important to remember that different freshwater fish have different lighting requirements.

Lighting for tropical freshwater fish

The most common tropical fish come from rivers, streams, and clean lakes in warm regions and are accustomed to bright sunlight and warming rays in a natural 12-hour cycle.

Therefore, to best recreate these conditions in an aquarium, you need to provide 12 hours of light per day, preferably using bright LEDs that penetrate the water surface, or use sunlight if the room where the aquarium is located is well lit.

Some species of tropical freshwater fish, such as tetras, may prefer low light. In this case, it is necessary to leave enough hiding places in the aquarium so that these fish can slip away.

Light for cold-water fish

Cold-water fish usually do not need excessive lighting. Only if the owner wants to admire the aquarium. Therefore, only 8 hours of light is sufficient.

If there are enough hiding places for them in the tank, even 12 hours of light is quite sufficient, especially if there are light-loving plants in the aquarium.

To create an optimal environment for cold-water species, the owner should try to adjust the aquarium lighting to seasonal daylight hours, as in the temperate climate zone where most cold-water species originate.

Light requirements for live aquatic plants

While lighting in aquariums is partly just for the enjoyment of aquarists, plants are largely dependent on daily lighting schedules, and good quality light is of paramount importance.

The light used in the aquarium and the duration of lighting will depend on the plants.

Some plants thrive in low light, while others need bright light for longer periods of time. For plants that like low light, such as Java moss, Java fern, and Anubias, 8-10 hours of low light per day is sufficient. These plants are also ideal for beginners.

On the other hand, light-loving species prefer:

• longer daylight hours, somewhere around 12 hours a day;

• adding CO2;
• fertilizing.

If the owner populates the tank with both plants and fish, experts recommend choosing aquatic plants that are suitable for the type of fish in the aquarium, for example, tropical plants with tropical fish.

Ideally, species such as platies, guppies, bettas, and catfish can be combined in aquariums planted with Java fern, Java moss, Anubias, hornwort, and Cryptocoryne. Goldfish, minnows, orrisia, and danios come from temperate climates where daylight hours vary and are best combined with different species of anubias and tiger lotus.

Light and algae

1-Siamese algae eater 2-Amano shrimp 3-Nerita snail 4-Glass shrimp

The most noticeable disadvantage of prolonged use of light is algae. Usually, if aquarists allow the light to work for more than 12 hours a day, blue-green algae grow exponentially.

In this case, however, you should be concerned not only about the lighting in the aquarium, but also about natural sunlight. If the aquarium is in a brightly lit room, it is not recommended to place it too close to the window.

However, algae will probably still grow in the aquarium, regardless of whether there is too much light or not, so it is important to control their size.

If algae thrive in your aquarium even at relatively low light levels, consider adding algae eaters: Siamese algae eaters, glass shrimp, Amano shrimp, and nerite snails.

Undoubtedly, light is crucial for both plants and fish in warm or cold water aquariums.

Yes, light is necessary in an aquarium — without it, both fish and plants will suffer. For plants, it is like food: without light, they will not grow and may start to rot. Light helps fish feel natural — it sets the rhythm of the day, as if they were living in nature: active during the day and resting at night. The main thing is not to overdo it: too bright light or a long day can cause rapid algae growth. It is good if the light is turned on and off at the same time — 8–10 hours a day is usually enough. A simple rule: there should be light, but it should be moderate and regular.

How long should the light be left on?

Frankly speaking, there is no definite answer to this question, since many factors must be taken into account, and only this answer is true. On average, we can say that the owner will need 10 hours of light per day for an average aquarium.

However, tropical fish and plants feel better with 12 hours of light per day, while cold-water fish and plants will thrive with only 8 hours of light per day.

Of course, if the aquarium only has fish and no plants, less light will be needed. Conversely, in a planted aquarium, it is better to keep the light on for about 12 hours.

A timer is a good tool for maintaining the lighting regime.

Aquarium lighting schedule

To begin with, you need to create an aquarium lighting schedule so that the owner can keep track of the lighting time.

Usually, this plan should include:

• clock;
• the time of day when the light should be turned on and off.

To relax and not worry about missing the right time, it is best to simply set a timer to turn off the lights at the same time every evening and turn them back on the next morning.

Should you leave the lights on in aquariums at night?

Proper lighting of the aquarium is important for fish and plants, but they also need a period of darkness so that they can rest and recover. Therefore, it is best to turn off the lights in the aquarium at night to mimic the natural light cycle of plants and fish.

Many beginners may not know this, but fish do sleep. However, most species do not have eyelids and depend on their owner to turn off the lights and provide them with enough hours of complete darkness so they can nap. Therefore, it is best to keep the lights in the aquarium on for the recommended 8-12 hours, then turn them off to simulate the natural day and night cycle.

If your fish become agitated when the lights go out, it is a good idea to turn off the overhead lights in the room an hour before turning off the aquarium lights. This should give the fish's eyes an hour to adjust to the lower light settings before complete darkness.

For plants, you should also gradually reduce the light level before turning off the light completely.

How to choose light

Lighting should be chosen based on the parameters of your aquarium and the desired result.

Intensity and spectrum

Not all light is the same. Intensity refers to how strong or “bright” the light is. Spectrum is a way of describing a mixture of different colors or wavelengths of light. The spectrum of light is often defined as color temperature.

Light sources that emit a yellowish or warm hue have low ratings, while light sources that emit a clear bluish-white or cool light have high ratings. Most lights for freshwater aquariums have a temperature between 5,500 and 8,000 Kelvin.

Intensity and spectrum are less important in aquariums with only fish or artificial plants. Too much light can promote algae growth, especially in aquariums without plants.

When it comes to live plants, the right intensity and spectrum can mean the difference between success and failure. Water depth also matters. Some wavelengths, especially blue ones, penetrate deeper into the water than others, and this can be crucial for live plants.

Type of lighting equipment

There are several types of aquarium lights, allowing aquarists to choose the one that best suits their needs and the needs of their aquarium inhabitants. Here are some common options for freshwater aquariums.

Incandescent lamps

If the owner uses old-fashioned incandescent bulbs, the lighting power should be about 25 watts per square meter of aquarium water.

However, incandescent lamps are outdated for several reasons:

• In most cases, they are ineffective at penetrating water deeper than 12 inches and illuminate the aquarium unevenly.
• They cause excessive heating and can heat the water above the temperature that was set to maintain heating, and then allow the water to cool when the lighting is turned off.
• Incandescent bulbs are very expensive to operate compared to fluorescent and LED lighting.
• They have a very short lifespan and can even break if water gets on them when turned on.

Standard fluorescent

For many years, this was the most common form of aquarium lighting, and it continues to be popular today. The affordable price and wide selection of lamps for various applications make fluorescent lamps an excellent choice for many aquarists. You can find strip lights and hoods, as well as a wide selection of lamps for rectangular, hexagonal, and curved aquariums.

Lamps dim over time and should be replaced every 10 to 12 months.

LED

Decor treatment

You need to be especially careful when feeding fish with tubifex worms, insect larvae, and copepods.

• To clean decorative elements and soil, it is recommended to rinse them with warm water and, if possible, soak them in a weak solution of potassium permanganate for a day, then rinse thoroughly and allow to dry.
• Filtration type: mechanical.
• Remember that a perfectly sterile aquarium is a myth. A healthy, balanced system always contains millions of creatures invisible to the naked eye. Your task is not to destroy them all, but to create an environment where beneficial bacteria and organisms are in balance and potential pests do not have a chance to multiply.
• Nematodes in an aquarium are not a death sentence. Most of them are completely harmless and even beneficial, as they participate in the decomposition of food residues and waste. Often, their appearance is simply a signal from your aquarium.
• Focus on maintaining cleanliness. Siphon the soil regularly, reduce feed portions, and check the filter. Often, these simple steps are enough to quickly reduce the population of threadworms without any chemicals.

If you cannot do without live food, it is better to buy it in specialized stores rather than harvesting it yourself.

This signal indicates that there is too much organic matter in the water. This is usually the result of overfeeding the fish or insufficient care. Therefore, the main thing is not to panic, but to restore order. Expert advice

Ease of operation and maintenance.

Ultimately, proper lighting transforms your aquarium from a simple tank of water into a full-fledged, living microcosm. Watching it is a pleasure. Experiment, observe the reaction of your pets, and you will surely find the ideal setting in which plants thrive and fish feel great.