Do Glofish Need Light At Night? Blue Light Harms Their Eyes?

Jan 25, 2022

Do Glofish Need Light At Night

Glofish look their best at night with blue aquarium lights turned on. Frankly, this is the sole reason for choosing to raise glofish for most of us. However, do glofish need light at night? Is it possible to turn the lights on at all times and marvel at their beauty without impacting their health?

I will tell you all about it in this article and some more. 

Stay tuned! 

Do Glofish Need Light At Night? 

No, none of the 5 glofish species are nocturnal. They remain active during the day and ‘sleep’ at night like us. Therefore, they don’t need lights on at night. It will only disturb their rest pattern and cause other detrimental effects to their health. 

Like us, glofish too have to have around 12 hours of brightness and 12 hours of darkness to function properly.

That’s a bummer, isn’t it? What’s the point of having glofish in the first place if you can’t enjoy their luminescent appearance?

I’m sure you’re pondering how to match your glowy friends’ sleeping schedule with yours, so you don’t miss out on all the fun. 

Don’t worry – we will work our way around it. 

What you can do is turn the lights on once the sun sets in the evening. And turn them off before you go to bed. 

This way, you’ll get to enjoy the beautiful view of your tank every day for a couple of hours. 

If you don’t think you can manually turn the lights on and off every single day, there are plenty of lights with easy-to-adjust automatic timers available for you to choose from. 

I’ve also tried to include a few answers hobbyists left on forums on the subject, so you view different opinions on a single platform. 

Let’s have a look. 

Do Glofish Need Light At Night? Honest Answers!

Note: All the answers mentioned below belong to the respective owners. 

“You should have it off at night.”

“You should probably turn off the lights at night – the fish will have a natural rest time – and also, the lights can get very hot.”

“Well, you can do some nighttime hours though – just when it gets dark, leave the lights on for a few hours.”

“I’ve always been under the impression that the best’ technique’ for lighting is to mimic a typical day/night cycle as closely as possible.”

“I don’t think it’s fair to your fish to keep the lights on at all times. It’s not natural. The fish exhibit very different behaviors under cover of darkness.”

Now the main query is answered, let’s branch out to other relevant and equally important topics. 

Recommended Readings!

What Glofish Can Live Together? 2022 Compatibility Guide

Glofish Barb Care Guide | Diet, Habitat, Breeding, Accessories

Glofish Shark Care Guide | Diet, Habitat, Breeding, Accessories

What Color Light Is The Best For Glofish? 

Deep blue LED lights bring out a glofish’s vibrant colors in the best way possible. They are deemed to be brighter and more suitable for daytime viewing. 

A combination of blue and white light is preferred for most aquarists. 

On the other hand, some hobbyists prefer black light for nighttime viewing to make the fish fluoresce more. However, the light will be dimmer. 

Here’s what a glofish tank looks like under blue light. Simply stunning! 

Are Blue LED Lights Harmful To Glofish?

Straight away, blue LED lights aren’t harmful to your glofish when used in moderation. However, if you keep the lights on for extended periods without a break, it will surely mess with your glofish’s biological clock and disturb its sleep pattern. And naturally, this will lead to unwanted consequences. 

Will Blue LED Lights Harm Your Glofish’s Eyesight? 

Research on goldfish in 2019 showed that irradiation with blue light for over a week induced retinal stress that could cause apoptosis in the retina. However, this was the only research piece on the internet on the topic. 

While I’m not doubting the credibility of the research, it’s essential to keep in mind that thousands of hobbyists across the world have been using blue LED lights in their tanks without any complication. 

One hobbyist on a forum commented that if fish consume plants like chlorella, enriched with mycosporine amino acids (MAAs), these organic compounds will concentrate in their ocular lenses and serve as natural sunglasses. 

So, if you’re really worried about blue LED light deteriorating your glofish’s eyesight, you can start giving them chlorella. 

You don’t really need to have a green thumb to grow these algae. It can be cultivated quickly at home in just a few simple steps. You just need to get your hands on chlorella culture first – it’s readily available on Amazon if you’re interested. 

Will Blue LED Lights Boost Your Glofish’s Growth?

Yet another research from 2004 carried out on species like silver carps, rotans, crucian carps, and guppies showed that the fish grew at the best rate under blue lights compared to red and yellow lights. 

Well, that’s some good news! 

Will Blue LED Light Calm Your Glofish?

The color blue is strongly associated with calmness and serenity. It’s known to impart an astringent effect. Therefore, we can safely assume that blue LED lights will calm your glofish compared to other colored lights. 

Since blue light mimics the natural moonlight effect, it helps to smoothen the transition from daytime to nighttime. 

Best Blue LED Lights For Glofish

Here’s a link to blue LED lights from the GloFish store itself suitable for tanks up to 55 gallons. 

I haven’t tried the lights, but the reviews look pretty promising to me! 

Check it out. 

Recommended Readings!

Is Blue LED Light Harmful To Fish? Can It Damage Eyesight?

What Does Blue Light In Fish Tank Do? What About Red And Green?

Okay, enough about blue lights for now! Let’s move on to a more exciting segment covering a glofish’s sleeping patterns. 

Do Glofish Sleep?

Yes, glofish do sleep. They definitely don’t sleep the way mammals do. But they will retreat to their favorite corners of the tank and rest. Their body will also secrete certain hormones that regulate their sleeping pattern and calibrate their internal clocks during this period. 

This is part of the reason why your glofish become passive when the night creeps in. 

Like all fish, glofish don’t have eyelids. Therefore, they don’t close their eyes when sleeping. However, their heart rate and metabolism will significantly drop. 

How Do Glofish Sleep?

Not all glofish sleep the same way. The sleeping pattern differs from fish to fish – even within the same species. While some like to retreat to a corner, others like hiding inside the caves or among plants. Some glofish will even sleep while afloat at the top or mid-region! 

How To Know If Your Glofish Is Sleeping?

Here are a few signs that show that a glofish is sleeping:

  • Your fish rests at the same spot at the same time every day. 
  • Your fish doesn’t respond to stimuli like food or light.
  • Your fish is in a still position. 
  • There’s no eye movement. 
  • The breathing pattern is slowed down. 

Frequently Asked Questions 

Before we end the article, let’s tackle some most frequently asked questions on glofish! 

Let’s begin. 

Why Are My Glofish Not Glowing? 

The most common misconception surrounding glofish is that they glow at all times. But this isn’t true. GLofish only ‘glow’ in low-light situations or under the blue or black LED light. 

That’s because glofish don’t produce the glow by themselves. Instead, they simply absorb the light from the surroundings and emit it back. 

Therefore, the environment needs to be dark for your glofish to emit lights the best they can.

Do Glofish Like Light?

Unlike plants, fish do not have a biological, indispensable need for light. And this applies to your genetically-modified glofish as well. 

Plus, we’ve never really had a conversation with glofish about their lighting preference. 

Jokes apart, I think glofish do like light – not all the time, though. Light helps them determine day or night and directly encourages their diurnal sleep cycle. 

Like all beings in the animal kingdom, captive-bred glofish too have adapted to a period of light followed by a period of darkness. Therefore, once again, I request you not to leave the tank lights on at night or 24/7. 

Do Glofish Need A Heater?

All 5 glofish species are tropical fish that thrive at a temperature range between 75-80 degrees F (24-27 degrees C). Thus, yes, they need a heater. 

Some hobbyists state that glofish danios can survive without a heater, but I’d still recommend against it. They can indeed thrive in comparatively lower temperatures than other glofish species, but they’d still need a heater to maintain a stable temperature for extended periods. 

If you keep your glofish at room temperature, which usually clocks in around 68-72 degrees F(20-22 degrees C), the fish will get stressed and eventually sick. 

Do Glofish Need An Air Pump?

An air pump is not as indispensable as a heater or a filter, but your glofish will definitely benefit from one. An air pump is essential for glofish because it increases the tank’s oxygen levels and promotes surface agitation and gas exchange.

Final Words: Do Glofish Need Light At Night?

No, as awesome as it’d be to keep the lights on at night and admire the fluorescent beauty, glofish don’t need light at night. 

Like most species in the animal kingdom, glofish, although made in labs, need roughly 12 hours of light and 12 hours of darkness. 

And that’s why you need to turn off those aquarium lights as the night falls. 

If the lights are turned on 24/7, it will mess with the fish’s internal clock. As a result, the fish will become disoriented, stressed, and sick. Worst-case scenario – your glofish will die an untimely death. 

Recommended Readings!

Glofish Danio Care Guide | Diet, Habitat, Breeding, Accessories

Glofish Tetra Care Guide | Diet, Habitat, Breeding, Accessories

Glofish Betta Care Guide | Diet, Habitat, Breeding, Accessories

rohit gurung author at urbanfishkeeping

About Rohit Gurung

My never-ending love and fascination with Aquascaping started when I received a red-eared turtle for my 10th birthday.

Apart from researching and writing, I spend hours gazing at my 3 turtles. And yeah, I bask alongside them too.