Algae in Turtle Tank

Algae in Turtle Tank

When it comes to turtle tank maintenance, one of the hardest jobs is controlling algae growth. Algae can cause your water to become a nasty green or brown color, and sometimes it can even cause your tank to smell. In today’s article, I will discuss some of the main causes of algae in turtle tanks, and also provide some tips on how to prevent algae from growing in your tank.

Types of algae in turtle tanks

There are 3 main types of algae that form in turtle tanks.

Green algae: This is the most common type of algae found in turtle tanks. This bright green algae is usually a long slimy substance and can form over objects in your tank. It can also attach itself to the tank glass. While green algae aren’t harmful to your tank, it can quickly grow and ruin the aesthetic of your tank.

bright green algae in turtle tank

Brown algae: This type of algae usually takes on a dusty look made up of very small brown particles. It almost looks like specks of dirt. Luckily, brown algae doesn’t grow as quickly as green algae, so it is a bit easier to manage. You can usually just wipe it away.

brown algae turtle tank

Blue-Green algae: While it is much less common, this slimy blue green substance can cover wide areas of space in your tank. It almost looks like a carpet. These algae can be toxic to turtles, so it’s important that you remove it quickly.

blue green algae in turtle tank

What causes algae in my turtle tank?

The main causes of algae growth in turtle tanks are excess light, dirty water, weak filter, warm temperatures, and overcrowding.


The main cause of algae boom in a turtle tank is excessive light. Algae needs light in order to process food and grow. If your turtle tank is sitting next to a window, there is a chance that your tank is getting too much natural sunlight. You also might be keeping your basking light on too much, which can allow algae to grow quickly.

Dirty water

Another cause of algae in a turtle tank is dirty water. Dirty water typically has very high levels of nutrients, and if the water has excess levels of nitrates and phosphates, it can fuel algae growth. To prevent dirty water, you should clean your turtle tank at least every 6 weeks.

Weak filter

If you don’t have a strong filtration system in your turtle tank, it can cause algae to grow. This is because the filter will not be able to breakdown enough waste, which will lead to a nutrient build up and potentially algae. You can learn more in my article on the best filters for a turtle tank.

Warm temperatures

Since algae thrives in warm temperatures, you might be assisting it’s growth by keeping your tank too warm. You want to make sure that your water temperature is between 75 and 85 degrees fahrenheight.


If you have too many turtles or fish in your tank, it can also lead to algae growth. This is because the increased waste can lead to an overload of nutrients, which in turn is food for algae.

What to do if you have algae in your turtle tank

Now that you know what causes algae to grow in turtle tanks, let’s talk about how you can remove and prevent algae from growing in the future.

Removing algae and water change

The first step is to remove any algae that is currently in the tank. Try your best to remove every little piece. I suggest that you do a complete water change, and also scrub down any algae spots on the tank glass. You should also clean off any decorations that you have in the tank. You may also want to clean your substrate if you have any.

Control lighting

Next, you should make sure to monitor the amount of light that is in your tank. If you turtle is next to a window that gets natural sunlight, I suggest putting blinds up on the window. As for your basking light, you should try keeping it on for only 10 hours per day.


If you have been struggling with algae for a while, I suggest you get a more powerful filter. This should help breakdown more of the waste in your tank, which will help control spread of algae. If you already have a powerful filter, you should make sure to give it a regular cleaning to keep it operating at a high efficiency.


While it can be tempting when your turtle is staring at you begging for food, it is important that you don’t overfeed them. If you feed your turtle too much food, it will cause them to poop a lot more which will cause more waste in your tank. Also, uneaten food can lead to increased bacteria levels which can cause algae.

Change substrate

While river rocks and gravel can give your turtle a nice, naturalistic aesthetic, they also give algae an easy spot to grow due to the surface area of the rocks. If your rocks are continually getting covered in algae, you might want to switch the rocks out for sand.

Live plants

While it can be hard to find a plant that your turtle doesn’t eat, live plants can help stop the spread of algae in your tank. This is because your plants can help take some of the sunlight and nutrients away from algae. Live plants can also help naturally breakdown waste in your tank.

Water changes

Water changes can help keep your tank water fresh and prevent the spread of algae. It will also help prevent the buildup of nutrients such as ammonia, nitrate, and phosphate. I suggest doing a 25% water change at least every two weeks.

Spot cleaning

You should also check on your tank every day and remove any visible algae. If the algae is on the glass, I suggest using an algae scraper.

Algae control in turtle tank

If your algae are still out of control in your turtle tank, I suggest trying one of the following:

Algae eaters: There are plenty of algae eaters that you can add to your tank. They will feed on the algae in your tank and help prevent it from getting out of control. You can consider algae eater fish or even algae eating snails.

Chemical treatment: I only suggest this option if you have already tried everything else. There are plenty of algae reduction solutions that you can buy online to help remove algae from your tank.


I hope this article helped explain how algae grows in a turtle tank, and how to prevent it from becoming a problem in your tank. The main key to preventing algae is avoiding the buildup of nutrients in your tank. You can avoid this by ensuring that the water in your tank is clean.