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Do Goldfish Eat Algae? What You Need to Know!

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By Lindsey Stanton

goldfish in a beautiful home aquarium_Videopozitiv_shutterstock

Algae can be a pain to manage in any aquarium, especially in aquariums with moderate to high levels of lighting. These levels of light can encourage algae growth, even causing large algae blooms on surfaces and in the water. If you have goldfish, you’ve probably noticed that they love to eat just about anything they can get into their mouths. It can be hard to keep planted tanks with goldfish because they will uproot or eat plants. So, it stands to reason that goldfish should help control algae levels, right? Read on for more info on goldfish and algae!aquarium plant divider

Do Goldfish Eat Algae?

Yes! Goldfish will eat many types of algae that grow in freshwater tanks and ponds. There are some varieties of algae, like black beard algae, that most fish, including goldfish, will not eat, making them harder to control.

Aquarium with water and goldfish_Lovbush_shutterstock
Image Credit: Lovbush, Shutterstock

What is Algae?

Algae is a type of plant that is almost always aquatic. It does not grow stems or roots and most varieties lack noticeable leaves as well. Algae photosynthesizes light for energy, so it thrives in high-light environments like well-lit aquariums. It is less complex than many plants, so it can survive in less favorable environments as well. There are tons of types of algae, but the most common types seen in freshwater tanks are brown or green diatom algae, hair algae, and green spot algae. Green tank water is also an indication of the presence of algae.

Is Algae Good for My Tank?

There can be complex answers to this question, but the most basic answer is yes and no. Algae can be unsightly and due to its ability to grow rapidly, it can take over tanks quickly. It can cause unsightly green water and too much algae can be detrimental to the nutrients shared with other lifeforms in tanks. It can also be difficult to control, especially once you have a full-blown algae bloom on your hands. However, algae, like most plants, does release oxygen into the tank and can help clear some toxins from the water, improving the health of your goldfish.

Is Algae Good for My Goldfish?

Algae is neither good nor bad for your goldfish. If they choose to eat it, it may protect the other plants in the tank from being eaten or uprooted by the fish. It can distract goldfish that enjoy scavenging for food, keeping them busy snacking on algae. Algae has little to no nutritional value for goldfish, so it is not a replacement for meals and fresh foods to graze on.

Many fish die as a result of improper food and/or portion sizes, which can be easily prevented by proper education.

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That's why our best-selling book, The Truth About Goldfish, covers exactly what you can and can’t give your goldies when it comes to mealtime. It’s even got a section dedicated to keeping your pet fish alive and well-fed when you go on vacation!

How Can I Control Algae?

In low to moderate lighting, algae may be easily controlled by routine tank maintenance and scavenging goldies. In more extreme algae blooms, algae-killing chemicals, like API Algaefix, may need to be added to the tank to get the bloom under control. There are also tank-cleaning brushes and magnets available to help physically remove algae from surfaces. Be cautious with these cleaning items if you have an acrylic tank because they can scratch the tank surface. If you are interested in keeping more than just goldfish, many aquarium creatures can help control algae including snails, shrimp, and Plecostomus varieties. Just remember that goldfish may eat any tankmate they can fit into their mouth.

aquarium plant divider

Final Thoughts

Algae can be a real pill to deal with, but your goldfish’s snacking habits may make this easier for you. Even if your goldfish is not a fan of eating algae, there are multiple options for algae control in your tank. Not providing more light than necessary to your tank will help minimize algae blooms and algae-eating fish and invertebrates can help keep low levels of algae under control. Remember that if your goldfish loves to eat algae that it is not nutritionally sound and is in no way a replacement for high-quality food and fresh veggies and fruits.

Featured Image Credit: Videopozitiv, Shutterstock

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