Can You Place Betta Fish Tank Under A Window?

my betta fish tank front view horizontal

Have you, too, seen all those pictures on the internet of well-decorated rooms with an aquarium by the window? If yes, I’m sure you wanted to try that as well. After all, it gives the room a different vibe, a good one. But can you place your Betta fish tank under or by the side of a window?

It’s better not to put a Betta fish tank under or by the window. Placing the tank under or by the window can cause temperature fluctuations, as the water will be exposed to direct sunlight. This exposure also promotes algae growth, which can potentially harm the fish.

But is there no good side to this? What if you’ve got no other room to put your aquarium? Well, that’s what I’m here to discuss today. Keep scrolling!

Key Takeaways

  • Keeping a Betta fish tank close or under a window is not suggested, as direct sunlight can mess with temperature and boost algae growth.
  • The good side of keeping Betta fish close to a window is it can influence the growth of water plants and save from additional lighting costs.
  • It’s better to use curtains, maintain temperature, and control algae if a tank is placed under a window.
my betta tank top view

Placing Betta Fish Tank Under A Window – The Good Side

Okay, I said it already – it’s not a good idea. But that doesn’t mean there’s no good side to this if you have no choice but to keep the tank under the window. It starts with –

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Exposure to Natural Light

What is the best way to under day-night cycles? The presence and absence of natural light, of course. When you’re putting your fish tank under a window, the Betta will easily experience that change in cycle, which will ultimately stimulate their natural behavior.

UV light from natural sunlight can be beneficial for bettas as it can help them regulate their day cycle. UV light also aids plant growth which enriches the environment. However, direct sunlight could overheat the water so an east- or west-facing window is preferable to a south-facing one. (source)

Growth of Water Plants

No matter what kind of plant you’ve got, all of them grow better when they get sunlight.

So, when the plants in your aquarium get that, they will surely have a better growth rate that will improve the tank’s aesthetics later.

Aesthetic Appeal

Who said only plants can add aesthetic appeal to your tank? The sunlight can do that if you’re putting it under a window. But for that, you’ll need a perfectly decorated room with an attractive focal point and a window that lets enough natural light come in.

Saving Lighting Cost

Why spend your bucks on lights when you have the natural ones? As the sun itself will cover the tank most of the time, it will cut your electricity cost down to a huge extent.

Replicating Natural Atmosphere

I bet you would love to give your fish the most natural atmosphere possible. So, when you’re putting the tank under a window, it will give the fish the same vibe it would’ve got in any tropical climate.

my betta fish tank front view light off horizontal

Why Under the Window is Not the Best Place to Keep Your Betta Fish?

That greed for an aesthetic look might push you to put your fish tank under the window. But it’s still not the best place for that because –

See also  Do Betta Fish Prefer Long Or Tall Tanks?

Fluctuation of Temperature

When you’re putting your tank directly under the sunlight, be ready to lose control over the temperature. Bettas are not designed to withstand overheating or frigid temperatures. So, if there’s an open window close by, it can overheat or cool down the tank unfavorably.

Algae Growth

Probably, I should’ve used the term ‘overgrowth’ here.

When the tank is exposed to sunlight for a longer time, it promotes algae growth. Not only will it mess with your tank’s aesthetic appeal, but it can also deteriorate the water quality.

Losing Light Consistency

Putting the tank under a window means you’ll have no control over the light. So, your fish will have everything but a consistent night-day cycle. The worst part is that it will mess with that natural rhythm of light-darkness and might trigger stress later.


You never know when your Betta will decide to make a jump. And if the tank is close to a window, one jump might be enough to lose your fish forever. So, putting the tank at a safe distance from the window is better.

Tank Maintenance Issue

The more sunlight hits your tank, the more frequently you’ll have to clean up. Excessive sunlight promotes algae growth. So, when the tank gets more than enough sunlight, it will pile up algae that you’ll have to clean up later.

Glare Issue

How can you possibly expect to enjoy the view of your tank when so much glare is blocking the view? Well, that might happen when too much sunlight hits your tank. So, no matter what kind of decoration you’ve used in your tank, you won’t enjoy much of it till the sun goes down.

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Tips to Follow While Putting the Tank Close to a Window

So you’ve got no other spot to set the tank? In that case, it’s the window spot you’ll have to go for. But make sure you’re following these tips while putting it there.

Using Curtains

You can’t dim the light of the sun. But can surely use blinds or curtains to stop it from hitting your tank. It won’t only help you manage the temperature fluctuations but also help you maintain a proper light/dark cycle.

Monitoring Temperature

Keep track of your tank’s temperature, especially when your tank comes in direct contact with sunlight. If it’s getting too hot, try changing the tank position. And if it’s getting too cold, try using a heater to bring back the comfortable temperature.

Managing Algae

Managing algae when the tank is exposed to the sun is quite a tough job. But that doesn’t mean you can’t keep it in control to a certain extent with efficient filtration.

Alternatively, you can keep some algae-eating species if it doesn’t stress out the Betta too much.

my betta fish tank front view

Before We Go…

It’s a known fact that Betta fish don’t like other fishes around. But what if you get one that likes other fish in the same tank, at the ones of their species? Well, I might be able to help you out on that with a blog of mine – Can Halfmoon Betta Fish Live Together? Click and check what I was talking about.

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Muntaseer Rahman

About Author

Hello, I’m Muntaseer Rahman, the owner of I’m passionate about aquarium pets like shrimps, snails, crabs, and crayfish. I’ve created this website to share my expertise and help you provide better care for these amazing pets.


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