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Can You Blind a Fish with a Laser Pointer?


Who hasn’t, at one point or another, had a laser pointer? 

Some people use it in their office, especially if they regularly do presentations. Using a laser pointer to call your audience’s attention to a specific part of your slide is one of the best presentation techniques to use when you want to emphasize a point.

For others, they associate it with the device that creates that tiny red dot that cats keep chasing after. They’re not wrong, mind you — a laser pointer does produce it. But this device has other uses, albeit these may be less known.

A fun fact is that cats aren’t the only animals that play with a red dot dancing across the floor. You might be surprised to know that you can use it to entertain other household pets.

At the very least, it’s amusing — at least for you. However, having a laser pointer isn’t all fun and games. You may think it’s relatively safe — after all, it’s just the size of a pen. Laser pointers are so small, you can carry one around in your pocket! 

But there are some things you should keep in mind to ensure your safety.

Are you ready to learn more about laser pointers and their potential hazards to your pets? Here’s more information that can help you out.

How Can Lasers Affect Fish and Other Pets?

Before anything else, let’s go back to basics. A laser pointer is sometimes referred to as a laser pen, mainly due to its shape and size.

Laser Pointer for Cats Dog and PowerPoint Presentations
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Most laser pointers are hand-held and typically powered by a battery. Inside, it contains a laser diode, which emits a beam of visible light.

Lasers can produce varying amounts of power. They come in four classes, each being more powerful (and potentially dangerous) than the last. Due to its size and usage, most people think all laser pointers fall into the lowest level category, but it isn’t necessarily true. 

Most pet owners have associated laser pointers as a source of entertainment for their pets without understanding that they also come with their own set of drawbacks. 

We’re not saying that you should completely throw away the idea of using a laser pointer as a toy, but knowing all the possibilities can be helpful regardless of whether you’re using it on cats, dogs, or fish.

Laser pointers fall under either Class 2 to 3, which means they aren’t as safe as you first thought they were. A lack of understanding of how lasers work may lead to accidents. Without meaning to, you may cause harm to yourself or even to your pets.

Do Fish and Other Animals Play With Lasers?

As mentioned earlier, some animals can’t seem to help but chase the dot from laser pointers. Cats are a primary example of this.

Cat plays with laser pointer

According to studies, it’s not the color of the laser point that catches their attention but its erratic movement. When the dot darts from spot to spot, it’s similar to how a prey moves. It, in turn, triggers a cat’s predatory instinct. 

The moving dot also provides cats stimulation, keeping them from feeling bored. When you turn your laser pointer off, you’ll notice that cats quickly return to what they were previously doing. You won’t observe the same type of response in other pets.

Dogs have a slightly different reaction. Like cats, they chase after the point a laser pointer creates because it moves. Dogs have a heightened ability to detect movement, so the continuous movement of the dot calls its attention. 

Similar to cats, a dog’s predatory system is triggered, which is why it cannot NOT chase after it. However, animal behaviorists have found that exposing your dog to this type of activity too frequently can lead to behavioral problems.

Dog plays indoor with stick and laser pointer

Although it may look fun to pet owners, the never-ending chase may cause frustration to your dog. It may cause them to become upset because they can never catch the moving dot. Eventually, you may notice that your dog becomes more challenging to handle, even if you aren’t using the laser pointer anymore.

Presently, studies have found another species showing the same type of behavior when exposed to a moving dot from a laser pointer: fish. Pet owners and marine biologists observed the same thing — some fish swim after lasers.

Several pet owners have noticed that their fish — whether goldfish, angelfish, or bettas — also chase around the dot projected by a laser pointer. Many think that their fish sees the moving dot as food, so it swims after it.

Some use it as a form of exercise for their aquatic pets. Others have found it to be an entertaining pastime.

Fish tank and laser pointer

Marine biology researchers noticed the same behavior in wild fish — they will chase a laser point on the seabed.

Although there isn’t any definitive reason for them doing it, a working theory is that they see the dot as a threat, and swimming after it is an attempt to ward it away from its territory. In turn, the distance they’re willing to chase the dot tells researchers how big their areas are.

Can Lasers Cause Harm to Fish?

Point laser on fish

The simple answer is yes. But a lot of it is dependent on how you handle the laser and how powerful it is. Don’t make the mistake of thinking that because you’re using a laser pointer, you can’t cause any damage.

If you’re not mindful about how you handle your laser pointer, you may put your pets through a difficult situation. Even fish, secured as they are within their aquariums, aren’t exempt from this. They may be more susceptible to the harmful effects of laser pointers than cats or dogs, who can just run from it.

Here are possible hazards lasers pose to fish:

It may cause blindness.

Fish have eyes similar to humans and other vertebrates, which means it is possible to blind fish, just as it’s possible to injure someone’s eye, with a mishandled laser.

Fish eye closed up

There are several differences between our eyes and theirs. One of these makes their eyes more susceptible to injuries from laser pointers.

Here are the main things that set fish’s eyes apart from ours:

  • Their eyes have an extra layer of film, allowing them to see better in water. 
  • They have no lachrymal glands (more commonly known as tear ducts). Since they live in water, they have no use for it. The liquid surrounding them cleanses their eyes.
  • Fish don’t have eyelids.

It’s the third one that’s significant. 

Pet Cat Laser Pointer
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If you’re using a 5mW laser, pointing it straight into the eyes of the fish may eventually cause damage to their eyes. Even with the extra layer of film, fish are technically unable to protect their eyes once the beam of a laser pointer hits them.

The other thing that may cause considerable damage is the color emitted by your laser pointer.

We know these come in different colors, red and green being the most common. Between these two, it’s the green laser that could potentially cause more damage.

Studies found that the spot emitted by the green laser is much more focused than a red one. The retinas also absorb green laser light faster.

If you put all those factors together, it means green laser pointers may cause more damage to the retina in a shorter amount of time.

It may burn their skin.

Danger laser radiation sign

Although the probability of this happening is lower if you’re using a low-powered laser, it is a possible outcome if you have a Class 3B laser. You may think you’re never going to use a higher-power laser, but you’d be surprised.

Class 3B is the category when lasers cease being safe for general use. The power produced by these lasers ranges from 5mW to 499mW.

Some pet owners use high-powered lasers to control the growth of algae in their fish tanks. Many see it as an effective method, but these can have multiple harmful effects on fish.

Not only can it cause eye injuries, but it may also cause the skin to heat up. Prolonged exposure, no matter how accidental, may lead to burns.

It may kill them.

Death fish lying on sand

If you’re attempting to clean your tank using lasers, make sure you’re wearing protective gear. Most importantly, get your fish out of the tank before starting the entire process.

Remember that when lasers hit the glass, it bends. Even if you aim it elsewhere, a reflected beam may be just as harmful as the original one and cause them to become blind almost instantly.

Some lasers can kill predatory crabs and vermetid snails, so it’s not too far off that they can also be a fish’s cause of death. If they’re left inside, the laser may severely burn them, eventually leading to their death.

In Conclusion

You know it’s annoying when someone directs a laser pointer’s beam at us. Why would you want to do it to your pets? A laser pointer may be a small thing, but now you know that it may also come with potentially harmful effects. 

Most people, however, assume all lasers are the same, but it isn’t true. Some lasers emit more powerful beams than others. The more your laser pointer produces, the more damage it may cause.

Even the color of your laser pointer has an impact. Remember, green laser lights are potentially more dangerous than red ones. It’s particularly true, especially when you’re talking about retinal damage.

Knowing these things and their possible effects can save you from accidentally causing harm to yourself, other people, and your pets.

Mind you, if handled correctly, laser pointers serve several purposes and can be helpful (and entertaining!). The best way to maximize our lasers and protect ourselves from injury is to know more about them.


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