Do Guppies Need a Light?

guppies need a light

Every fish tank requires a light, right?

Not quite.

Lights in fish tanks are not really required for the fish – they are required for plants (and humans), but not the fish. This rule of thumb applies to guppies as well. Guppies do not require a light. The sunlight that comes in through your window or from your lamp is enough light for a guppy to survive.

In fact, it’s probably better that a guppy does not have an artificial light. Here’s why.

Why You Don’t Need a Light in Your Guppy Tank

Here are some reasons you don’t need a light in your guppy tank. Of course, you probably want one if you don’t have a light source in the room your aquarium is in (ie. a basement), but these are general guidelines for the most common use case.

Guppies Sleep

First of all, guppies do sleep. Have you ever seen your guppies at night staying still in the tank?

That’s the fish version of sleeping. And, just like humans, it’s much easier for fish to “sleep” when they don’t have a bright LED shining in their eyes.

Granted, you could turn off the light at night, but many owners forget to do this for one reason or the other. Life gets in the way of managing a fish tank.

Sunlight is Enough for Guppies

sunlight guppy tank

You most likely have your fish tank in a room that has some sunlight coming in through a window or has a light in the room, right?


That sunlight or artificial light from the overhead light should be enough light to keep the guppies happy during the daytime. The sun also goes down at nighttime, which keeps the fish on a good natural cycle. As you probably know, a natural cycle is the best way to minimize stress.

Low stress fish have a tendency to live longer. And in the case of guppies, the males will have more vibrant colors if they’re less stressed out.

The downside with relying on sunlight to light your fish tank?

You will have to clean a lot of algae. I did this with a small 10 gallon tank in a very well lit room. It worked fine for the guppies and they seemed happy. But it was annoying because the tank required cleaning algae off the glass almost every week and vacuuming every month.

That’s the downside of having too much light in your fish tank – algae everywhere.

On the bright side (pun intended), the plants did well with all the sunlight.

Cheap Lights Are Bad

If you have a fancy fish light, then this point does not apply to you.

Unfortunately, most guppy owners rely on the cheap lights that come with a PetSmart or Petco fish tank.


Those lights do not have a great reputation. They’re a little too bright and a little too blue, which will stress your guppies. Again, stressed guppies do not live as long and have duller colors.

Those cheap lights also have a tendency to “burn” the plants. My plants always had yellow spots on them from the bright lights shining on them. Additionally, the plants could not absorb that spectrum of light.

Honestly, it was pretty much a waste of money having a cheap light and I eventually decided to go au natural with my lighting for that tank.

My guppies and plants were much happier. But I did have to clean algae more often.

In my opinion, you’re better off simply using natural light for your guppies than relying on a cheap tank light. A higher quality light is the best choice, though. But I fully understand it’s not in the budget for many people.


So, our opinion is that guppies do not require an artificially lit tank. The light from the sun or your room will be enough light to make your guppies happy.

However, you have an aquarium to look at it, so you will probably want a light for the tank. In that case, make sure that you purchase a high quality fish tank light for your guppies. A low quality light will stress out the guppies, which can cause discoloration and a shortened lifespan. It will also “burn” and possibly kill your plants.

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