Freshwater Aquarium Lighting


The following is information on lighting in a freshwater aquarium. In general, lights are not as important in a freshwater aquarium compared to a high-tech planted aquarium or a saltwater aquarium. There will be another page discussing the importance of lighting in a high-tech planted tank. In the mean time, if you have a simple aquarium with no plants or low light plants such as Java Moss, the type of lighting you use is probably not too big a deal.

If you pick up a used freshwater aquarium and it comes with an older fluorescent light, the light will be perfectly fine for your tank. It will not be as good as a newer and brighter LED lights that will make your tank brighter which will make your fish clearer when you are observing them. One factor to keep in mind when selecting lighting is that a stronger light will provide more energy which could mean algae.

Importance of Lighting in a Freshwater Aquarium

Lights for a freshwater aquarium that doesn't have any plants or has low light plants serve a few purposes:

  • Allow you to observe the inhabitants of the aquarium
  • Helps provide a day and night cycle of your tank which is not as important if your aquarium is located in a room with a window
  • If you have plants in your tank (Provides light for them to photosynthesize)

Different Types of Lighting

Lighting has come a long ways from how tanks were 10 to 20 years ago. We've gone from normal output fluorescent lighting to compact fluorescents (CFL) to affordable and bright LED lights. The following is a brief discussion of each type of light:

Normal Output Fluorescent Lighting

This is probably the type of light that will come with a fish tank if you purchase a used older fish tank. The bulbs are the longer tubes which come in a wide range of colors. The main con with this type of lighting is that it is not very bright compared to CFL's and LED's. Because we are discussing freshwater aquarium lighting in this page, we will not be going into detail of the different types of lights because:

1) In an unplanted tank or a tank with low-light plants, pretty much any type of bulb is going to be fine. There are some bulbs for specific purposes, but overall unless you're unhappy that the light is too dim or that the color it is emitting isn't bringing out the best in your aquarium fish, the bulb is not going to do much except for the purposes mentioned above. Low-light plants should be okay with any type of bulb as long as there is some light

2) Most new aquarium fish tanks are equipped with LED lights these days. The cost of LED lights has greatly decreased since they were first introduced and they are at a point that most consumers with disposal incomes can afford to purchase them


  • Probably free when purchasing a used older aquarium


  • Very dim (you won't be able to see your fish very well)
  • Flickers a lot
  • Probably can't find replacement bulbs

Compact Fluorescents

CFL's are found in do-it-yourself aquarium lighting systems as well as some substantially large aquarium lighting systems. The benefit of CFL's are that they are long lasting, bright, smaller size, and they are a strong enough light to allow plants with higher light requirements to fluorish. In the budget planted tank, some aquarists will set up CFL's using desk lamps to light their tanks and will have great success doing so.

If you are interested in going this route, I suggest looking up CFL lighting for aquariums on YouTube. If you are just operating a tank and don't want the hassle of dealing with desk lamps and etc, you'll probably want to pick up an LED light.


  • Cost effective aquarium lighting solution
  • Provides stronger light than normal output fluorescent lights (Allows you to grow plants that require medium light)


  • Can get very hot (if aquarium water splashes on a light, it will probably break)
  • Do-it-yourself set ups with desk lamps are not very attractive


LED's are the new generation of aquarium lighting. Not only are they the brightest lights for regular freshwater aquarium consumers, they are quickly becoming very reasonably priced. Some LED lights are also dimmable, so you can adjust the brightness in your freshwater aquarium. LED lights are also strong enough for high tech planted tanks and are small enough fit in the design of many of the nano tanks that are out there.

If you do not have a high-tech planted aquarium, you will need to be conservative with how often an LED light is on. Because LED lights are so strong, if you keep them on as long as a normal output fluorescent lighting, there will probably be algae issues. This was the case in a low-tech planted tank I owned, but you couldn't beat the brightness in the tank and the amount of detail that you just can't see with a dimmer light.


  • Bright
  • Comes in a variety of colors (Certain colors are going to make your aquarium fish and plants stand out more)
  • Becoming very cost effective


  • Can be too bright which can cause algae growth


In conclusion, aquarium lighting is important in the sense that it will allow you to enjoy your fish tank. If you are new to the hobby, a tank without a light is like a dim or dark room. Fish will be dark shadows in the tank and you will not be able to fully enjoy their colors. If you are buying a new aquarium kit, it should come with a light, if it doesn't make sure to pick up a light that suits your tank size and needs. In most cases, you will probably want to pick up an aquarium LED light. There are multiple brands out there these days which has led to the decrease in price. In any event, the consumer always wins with competition and the more competition the better!