Do Fish Tanks Need Light? Read This First!

When first starting to setup an aquarium, there are some things you’re going to need and others you don’t. Generally, fish will require a water filter, air pump and some sort of lighting.

But do fish tanks need light? In most cases, yes they must have some form of light. But, there are a few exceptions. However, this will largely depend on the kind of fish you have and the general lighting environment of their native habitat. Some fish prefer low to no light situations but most require some degree of it.

However, you may not have to buy a light. You can opt to use indirect sunlight if the space allows for it. That said, it’s always better to buy a light so you can control the conditions as needed.

What Is the Purpose of Light in an Aquarium?

Fish, like people, require cycles of light and darkness to maintain health and reduce stress. But, unlike people, they also need some light at nighttime. However, it’s important to understand that you don’t want to have light on them every day of every hour.

Likewise, if they remain too long in darkness, it can negatively affect their health. Their immunity will weaken, become lethargic and they may not eat too much. All these symptoms result in a sickly fish that may be difficult to heal.

Also, having light in your aquarium will stimulate the fish to move and swim around. This is the best way to keep them fit and active so they stay healthy throughout their lifetime. A lack of light will cause a form of depression and it can make them sick.

How Do You Ensure Fish Get Enough Light; Darkness?

The best way to ensure your fish get the appropriate amount of light and darkness is by putting artificial lights on a timer. You won’t have to worry about them too much in this regard when you do it this way. But, you can also use sunlight for this as well. It all will rely on where you have the tank and how much light enters the room.

12 Hours of Both Light ; Dark

Make sure fish receive at least 12 hours of daylight and 12 hours of darkness. But, the trick is to NOT have your artificial light shining on the tank for the entire 12 hours. This is because algae blooms will grow to a disturbing degree that will become very hard to control.

So, you will have to play around with lighting, timing and lengths of leaving the lights on/off. Once you come up with a combination that works, you should be able to control algae blooms to a satisfactory level.

Controlling Algae Blooms

Therefore, keep your light on for about eight or nine hours. If you don’t see any algae developing, then go ahead and push it to 10. You’ll have to play with the time and strength to see what works best. This will be ideal in ensuring your fish get enough light while avoiding the dreaded algae bloom.

Some people even shorten or break up the time they keep the lights on and off. Some people will keep them on for intermittent lengths, like four hours on and then another four hours off. They maintain this throughout the day. Not only does it ensure fish get enough light but it alos control algae effectively.

How Do You Use Sunlight for an Aquarium?

Sunlight is tricky business in regards to an aquarium. Never put your tank in the way of direct sunlight. This will heat up the water and make your fish incredibly uncomfortable, especially if they are specific about the temperature in which they reside.

However, if you can put the tank in a room where it will receive indirect light from a window, then you can technically scrap buying a light altogether. Another way to filter strong sunlight is to have a planted tank. The plants will absorb sunlight and, via photosynthesis, will produce oxygen in the tank.

How Long Should Fish Have a Light on at Night?

Keep your light on for two or three hours after sunset and then turn it off. Other than that, fish don’t require nighttime light. If you leave the lights on all night, not only will it sicken your fish but it will cause algae blooms to proliferate in the aquarium. The only caveat to leaving the lights on at night is if you have intermittent timing of the lights.

However, you also want to consider moonlight. This means keeping a light on somewhere in the distance and following the moon’s phases. This will create a more natural environment for your fish. Your artificial moonlight should not be strong or hot.

Can You Use Colored Lights for an Aquarium?

You can use colored lights for an aquarium, if you wish. But, this is going to be for highlighting the iridescence of your fish’s scales rather than for the benefit of the fish. However, never use changing RGB lights or lights that flash/flicker. This will create stress on your fish and it will freak them out.

Having said all that, you should also have a white light that mimics daylight sitting in the range of 5,000 to 6,500 K. Understand that fish must have a fairly stable environment that doesn’t change too much or divert from their natural habitat.

Are There Any Exceptions to Needing Light for Fish?

There are only a couple of exceptions where fish won’t need any light at all. Fish that are blind or ones who’s natural habitat is dark won’t require it. For instance, fish that come from the darker, murkier waters of the Amazon River won’t want too much light, if any at all.

This means you have to research your particular breed of fish to understand what they require. But, even if your fish doesn’t need a lot of light, you want to have some kind of light around so you can see your fish, check the tank and have an enjoyable experience overall.

Can You Use Ordinary Light Bulbs for a Fish Tank?

Do not use ordinary light bulbs to illuminate your aquarium. These produce yellow light that’s a far cry from natural sunlight. Plus, it outputs far too much heat and it will cause fish great harm and discomfort. This is especially true if you’re already using a heater and the ordinary light bulb stays on for a long period of time.

What Is the Best Kind of Light for a Fish Tank?

Ensure you purchase fluorescent or LED lights that rest above the tank. It is imperative that it simulates natural sunlight as much as is possible. The good thing about LED lights is that they are inexpensive to run and they don’t get very hot, even after many hours of being on.

Also, make sure you have a glass covering between the water and bulbs. This will be soothing for fish and for you. Plus, it will ensure the water doesn’t heat up due to the light source constantly beaming on it.

Are Plants Necessary for Light Setups in an Aquascape?

If you have a planted tank, you will have to use a light to ensure they stay healthy and grow without polluting the tank. But if there aren’t any plants at all, then you don’t really need to have one. Yet, this will largely depend on where you have the tank and how much natural light enters through the window.

For example, if your tank is in the basement where not much sunlight shines through, you will need artificial light even if there aren’t any plants. But, if you have your tank in the living room, then you shouldn’t have to buy a light at all. Just make sure there’s a water heater and adequate filtration.

How Much Do Aquarium Lights Cost?

The average aquarium light can cost anywhere between $20 and $30. Of course, this will depend on if you’re getting an LED or fluorescent one. Generally, LED ones are less expensive than fluorescent and they last a lot longer too.

The most reliable and trusted brands of lights for your tank will be from one of the companies listed below. There are others worth looking into, but these ones have the best quality for the right amount of money.

• Aqueon
• CurrentUSA
• MarineLand
• Glo