Do Goldfish Eat Algae? (All FAQ’s Answered!)

Wondering whether goldfish eat algae? And more importantly, if it’s going to be good for them or not. In this article, not only will you find this out, but you’ll also learn whether you can feed your goldfish algae wafers, whether too much algae can kill your goldfish, and much much more!

So keep reading to find out everything you NEED to know about goldfish and algae!

Do Goldfish Eat Algae?

When it comes to food, your goldfish will pretty much eat anything. So yes, goldfish are also going to eat any algae they come across when they’re hungry. And the thing about goldfish is… they’re always hungry.

Is Algae Good For Goldfish?

Algae has little nutritional value to offer goldfish; however, it’s not harmful either. As long as your goldfish is getting a balanced diet and aren’t overloading on algae, it’s going to be neither good nor bad for them.

If you’re going to let your goldfish eat algae, make sure that you’re supplying them with live food, high-quality fish flakes, and vegetation like peas and lettuce to make sure they’re getting enough nutrients!

And lastly, remember, if there’s too much algae, it’s still not good for your goldfish. Too much algae can kill the plants that goldfish eat and provide them with actual nutrients.

Can Goldfish Eat Algae Wafers?

If algae have no nutritional value for goldfish, then you may be wondering if it’s even worth feeding them algae wafers. Algae wafers are actually better for goldfish than algae alone! They don’t just contain algae but a whole range of nutritious ingredients. Oftentimes including fish meal, spirulina, pea protein, dried seaweed meal, and other vitamins and minerals.

So while algae wafers can’t provide your goldfish with all the nutrients they need, they’re still going to be able to provide them with a good amount!

Do Goldfish Eat Algae In Ponds?

While goldfish are going to eat algae in ponds, they’ll never be able to keep up with the speed at which algae grows. So you shouldn’t rely on them as the only way to remove the algae. In fact, goldfish add to the algae problem by creating nitrates, nitrites, and ammonia which feed algae!

To remove algae in ponds, you’re best off adding lots of plants to the pond. This causes the algae to compete for nutrients, and it will begin to die off. Water lilies are a great choice, as well as water hyacinth and duckweed. You should use floating plants as they’re better at killing off algae.

If there’s still too much algae, you can also use API Pond Algae Fix to remove algae from your pond as well.

Will Your Goldfish Eat String Algae?

It may look like string algae is going to be hard for your goldfish to eat, but they’ll happily eat it. Once again, remember, though, that goldfish alone won’t be able to remove it. In fact, you’ll need to act quickly to remove string algae as it can reduce oxygen levels in the water dramatically. As well as this, it can also strangle other plants, and sometimes fish can even get trapped in it and die.

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Do Goldfish Eat Algae Eaters?

You may be thinking that the simplest solution is to just add algae eaters to your pond or tank. The only worry is that your goldfish might eat them. The truth is goldfish can and will eat algae eaters smaller than them. Not every goldfish, but remember, they are omnivores, so anything smaller than them is definitely going to be considered food.

You may get away with putting larger shrimp or snails in with them when they’re small, but as your goldfish grows, they definitely won’t be safe.

If you want to add algae eaters anyway, then plecos are generally recommended. Rubber-lipped plecos are your best bet as they’re peaceful fish and will often keep themselves to themselves.

If you want rubber-lipped plecos, you can also try Bristlenose Plecos as well. However, be warned Bristlenose plecos can often be semi-aggressive to other plecos in the tank.

When you’re adding either pleco, make sure you’re supplementing their diet with vegetables and algae wafers, as algae on its own won’t be enough to sustain them.

Another problem some goldfish owners have reported is that plecos may try to eat the slime coat off of a goldfish. When this happens, you’ll notice sores on your goldfish that are prone to bacterial infection. So make sure you’re keeping an eye on your goldfish if you have plecos, and if you notice sores, you’ll need to remove them.

Can Too Much Algae Kill Goldfish?

This really depends on the type of algae. Some algae release toxins into the water that can kill goldfish over time. As well as this, algae, like all plants, is going to produce more carbon dioxide at night, lowering the oxygen saturation in the water. And when the oxygen content in the water decreases, your goldfish and other fish may struggle to breathe!

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What Causes Algae Growth?

There are a number of things that can cause algae growth. So you may want to consider doing what you can to reduce algae growth in your tank at all! Here are a few of the main culprits that cause algae to grow.


When you overfeed your goldfish, they won’t be able to eat all the food in the tank. If you don’t remove the food, then it’s going to sink to the substrate and rot. While it’s rotting on the substrate, it’s going to produce nitrites and nitrates, which is exactly what algae need to grow out of control.


When overstocking occurs, waste and decaying matter will build up faster than it can be removed. Nitrate and nitrites will begin to grow out of control, once again giving algae an abundance of nutrients.

You always want to make sure you’re not overstocking your tank or pond to reduce this from happening.

Too Much Light

Too much light, especially sunlight, is going to cause algae growth to occur rapidly as well. If you’re keeping your goldfish in a tank, you should move the tank somewhere that isn’t in direct sunlight. And if you’re keeping your goldfish in a pond you want about 60% of the water surface to be covered with floating plants. This helps reduce the sunlight getting in.

Not Enough Cleaning

If you’re not cleaning your tank regularly, then the waste is going to build up. You should be vacuuming the gravel as well as performing water changes weekly. This is even more important with goldfish as they’re especially dirty fish.

Not Enough Plants

Lastly, you need to make sure you have plants to compete for nutrients. When there aren’t any plants, algae has free reign to grow and grow and grow. Adding lots of different plants will help slow the spread of algae, plus it makes the environment nicer for your goldfish!


Now you know that goldfish can eat algae; however, there’s no nutrition in it, so it’s neither good nor bad for them! However, too much algae can be damaging as it can release toxins that make your goldfish sick!

If you liked this article, make sure you check out the rest of the website; otherwise, have a great day!

About the author

Hey there! I'm Antonio, the passionate owner and chief editor of Betta Care Fish Guide. With over half a decade of hands-on experience, I've become your go-to expert for all things betta and tropical fish.

Over the past 5 years, I've not only kept bettas and other tropical fish but also connected with a diverse network of hobbyists, seasoned fishkeepers, and even veterinarians.

Now, I want to help other beginner fish keepers who had the same questions as me when they were just starting out! So they can save themselves a ton of time and keep their fish happy and healthy!