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Do Angelfish Eat Algae? (With 6 Prevention Techniques)

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When I first introduced angelfish to my aquarium, I wondered whether or not they eat algae. Personally, I liked how my aquarium looked, and I didn’t want the angelfish to ruin it. Also, I wondered if it might hurt them if they eventually chose to nibble on it. That was when I began to research the topic a little deeper.

Yes, angelfish eat algae since they are a part of the Pomacanthidae family, which are known to be omnivores. Therefore, they would eat both animal matter and plants; algae included. Also, angelfish are voracious eaters, and as a consequence, they always have an appetite.

Hence, if you own angelfish, their Pomacanthidae characteristics[1] as omnivores[2] will derive them into eating your plants and algae. Nevertheless, there are a few ways to prevent this from happening, as I will elaborate later on in this article.

Also Read: What Do Angelfish Eat?

What Kinds of Algae Would Angelfish Eat?

To make it easier for you to recognize your angelfish behavior, I have arranged a list of five kinds of widely seen algae. Hopefully, you will be able to find the specific type that grows in your aquarium and get a better idea of whether or not your angelfish consumes it.

1. Slime Algae

This type of algae gets its name from its appearance, which resembles the form of slime. Also, instead of appearing in a bunch, it appears in the form of small dots. It grows not only on the aquarium walls but also on the fixtures inside.

It is one of the most common types of algae that you might encounter if you own an aquarium. This kind of algae is usually troublesome to fish owners since it spreads and gives off an unpleasant odor.[3]  The good news is that angelfish are very likely to consume it, with the Centropyge genus in particular.[4]

2. Thread Algae

Thread algae (also known as filamentous algae), appears in the form of thin strands, which are very accessible to plants eating fish. This subtype tends to spread via currents in the aquarium, and regrow in different areas.[5]

As you might have already noticed, angelfish are nibblers. As such, it is likely to see them bite the stands regularly. From my experience, they actually consume it pretty enthusiastically. 

Thread algae usually add beauty and natural sense to your aquarium. Hence, fish growers generally prefer their fish to stay away and stick to their designated diet. Nevertheless, if you grow small groups of fish in your aquarium, they would probably have little effect on the plant.

3. Brush Algae

Have you noticed any algae in the aquarium which appears like hair? If yes, this is probably the brush one that you have witnessed. It often appears on plants, particularly around their edges.

Not all fish eat this, but you shouldn’t be surprised if your angelfish does. Also, consider that angelfish are pretty gentle and might get caught in this kind of algae’s hair.

4. Green Dot Algae

The name of these algae is based on their characteristic appearance. It appears in green dots on fixtures as well as on aquarium walls. One of the disadvantages of this type of algae is that it is rapidly multiplying.

That is why, soon enough, it can cover the entire glass. Some angelfish might eat it, but due to the quick multiplying nature, the algae will continue to spread. If you have green dot algae in your aquarium, irrespective of whether your angelfish eat it or not, you will need to clean it out.

5. Fuzz Algae

Fuzz algae are in the form of long strands, pretty similar to thread algae. However, the strands here are usually thicker. It is often used in aquarium decorations, as well.

Angelfish, as well as other fish, might consume this type of algae. The multiplying rate of these algae is on the lower side, and therefore, even if you have a few strands in your aquarium, you can keep them under control.

Thus, if you’re wondering whether or not angelfish consume algae, the answer is a definite yes; it is certainly heard and seen. Here are a few quotes from people online who have experienced the same thing as I did:

“My angels that I had would frequently pick at algae in my tank. As Gerry said they are voracious eaters and more prone than other fish to overeating.”

“I have observed my Angels eating Hair Algae only. As a matter of fact, most fish will pick on Hair algae.”

“My long gone angels liked the long green filamentous algae they could only get when I pulled the hornwort out of the tank, they went nuts for it!”

Can I Stop Angelfish From Eating Algae?

Many aquarium owners want the fish to stick to fish food. It ensures that they get a well-balanced diet. If you, too, want your angelfish to stop eating algae and stick to their designated food, there are steps that you can take. These include:

1. Increase The Feeding Frequency

One of the best ways to stop angelfish from consuming algae is to increase the feeding frequency. When they have ready-made food available in the aquarium, angelfish are less likely to resort to eating algae. It will ensure that you can significantly reduce their algae consumption.

2. Try Other Kinds of Food

Even though angelfish are not picky, they may prefer one kind of food over another. In this case, they can resort to eating algae. That is why I suggest you try changing their regular diet.

Many times we miss the ideal kind of food on our 1st attempt. There is nothing wrong with it. However, once you go through some trial and error, chances are you end up picking the right dish for your fish. 

As time passes by, you will be able to notice changes in the algae growth. If your angelfish rely more on the food you provide them, they probably nibble the algae less frequently.

3. Provide Angelfish With a Balanced Diet

When talking about an angelfish diet, you must consider some other kinds of fish food. If you diversify their meal, they will get more crucial nutrients they might have missed from previous feeds. You may additionally consider:[6]

  • Bloodworms
  • Mysis shrimp
  • Brine shrimp
  • Flakes
  • Zucchini
  • Cucumbers
  • Shredded Lettuce

Doing so ensures that the fish have plenty of food options. Also, generally speaking, they are bound to like some of these foods better as compared to others.

When that happens, you can increase the proportion of those foodstuffs, so they rely less on algae. A balanced diet also ensures that the fish are healthy, and as a consequence, live longer.

Mysis Shrimp

4. Eliminate Algae From Your Aquarium

The most obvious step that you can undertake is to remove algae from your aquarium. It might be easier said than done. However, there are ways to do so. I prefer to choose between one of the following methods:[7]

Get a Few Active Algae Consumers

You can introduce algae-eating fish in your aquarium. Angelfish nibble on algae, possibly. However, algae-eating fish feast on them actively and, therefore, reduce (and might even eliminate) their presence in the tank.

A few examples of such fish would be:[8]

  • Siamese Algae Eater
  • Twig Catfish
  • Otocinclus Catfish
  • Bristlenose Plecos
  • Mollies
  • Snails

Dim Off The Lights

There are types of algae that can survive in absolutely no light. If there are natural plants in your aquarium, you do not have the option to switch off the lights.

However, in case your aquarium features artificial plants, you could dim them a little. Doing so ensures that the growth of algae gets hampered.

Nevertheless, you need to make sure that there are proper day and night cycles for the angelfish to thrive. That is why it is a delicate balance to achieve.

Add a Few Natural Plants

If you cannot opt for the light method, it is better to go for as many natural plants in your aquarium as possible. Doing so ensures that algae seldom get food, as the other plants will be competing with them. It might hamper the growth of algae, hopefully eliminating it eventually. 

Get Yourself a Few Floating Plants

Another option is to opt for floating plants for your aquarium. It ensures that the amount of natural light that reaches algae is lower. At the same time, it competes with algae for food, as well.

The floating plants often absorb a lot of phosphates as well as nitrates, leaving smaller portions for algae. As time passes, you may start noticing that the algae growth is prohibited, while the floating plants flourish.

These are some methods that you can choose from to eliminate algae from your pool. Once removed, the angelfish will have no other option but to stick to the fish food that you feed them.

5. Create a Proper Feeding Schedule For Your Angelfish

Many times, if your feeding schedule is not correct, angelfish have no other resort but to nibble on algae. That is why you should not just increase the frequency of feedings, but also ensure that you do so at a fixed time.

It will mean that angelfish always have access to fish food rather than relying on algae. Regarding feeding frequencies, try giving them food two to three times a day, especially during their younger years.

6. Clean The Aquarium Regularly

The method that I am going to highlight now is suitable only for algae that grow on rocks, as well as other solid surfaces. There is no escape from it; you do need to clean all of them from time to time. Doing so will also eliminate food leftovers, so algae will find it more challenging to regrow in the future.

Does Angelfish Eating Algae Indicate Anything?

When angelfish starts eating algae, many aquarium owners want to know if it is due to one of their mistakes. Well, it is not necessarily due to the owner, but it surely can indicate something.

Angelfish that eat algae may suggest things like:

  • The food which you feed them is not sufficient.
  • They do not like the food that you feed them.
  • You need to feed them more often.
  • They cannot compete with other fish for the food that you feed them.

In most of these cases, you can stop them from eating algae just by helping them consume a balanced diet and feeding them regularly. However, if they are only nibbling on algae, it is not necessarily harmful in the long term. It is when algae constitute a significant part of their diet, can problems arise.

Is Algae Good For Angelfish?

Since it may seem unnatural, some of you might wonder whether or not algae could harm your angelfish. That may also lead to the thought that you should clean your aquarium much more frequently, so it doesn’t have algae growing. 

Well, that isn’t entirely true, since algae are quite suitable for angelfish, and to your community tank in general. There are a few advantages to it[9]:

  • Algae reduce nitrogen compounds, which may be toxic to your fish.
  • Like many other living planets, algae dissolved oxygen in the water.
  • Algae help in maintaining the biological balance in the aquarium.

Nevertheless, once it dies, it may release all the nitrogen compounds which were previously absorbed. Therefore, it is not recommended to have too much algae in the aquarium. The key here is a balance, and you should pay attention to it.

Also Read: Do Angelfish Eat Plants?


Angelfish consume different types of algae. That is why, if you have bothersome algae growing in your aquarium, angelfish may help in reducing it (especially if they are in large groups).

In most cases, if they nibble on it rather than consuming it at a brisk pace, you shouldn’t be worried about it. However, if you want them to shift to fish food, you can follow any of the six methods that I have highlighted above.