How to Get Rid of Brown Algae in Fish Tank

By Algal Web

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Maintaining a clean and healthy environment for your fish is crucial to their overall well-being. Unfortunately, brown algae can often become an unwelcome presence in fish tanks, causing aesthetic issues and potentially harming your fish. 

In this in-depth guide, we will explore the causes of brown algae growth and provide you with a step-by-step approach to effectively get rid of it, ensuring a pristine and thriving aquarium for your aquatic friends.

Understanding Brown Algae

Brown algae, scientifically known as diatoms, are single-celled organisms that commonly manifest as a brown or yellowish film in fish tanks. These algae thrive in freshwater and saltwater aquariums and can be quite tenacious. Understanding their characteristics and causes is essential to effectively combat their growth.

Brown algae often proliferate in new aquariums or tanks that have undergone recent changes. They take advantage of excessive nutrients, such as nitrates and phosphates, as well as ample light exposure. Additionally, the presence of brown algae can indicate underlying water quality issues.

Prevention Measures

Taking proactive measures to prevent brown algae growth is the first line of defense. By establishing proper tank setup and maintenance practices, you can create an environment that discourages the growth of brown algae.

1. Proper tank setup and maintenance

It is crucial to cycle your tank before adding fish. This process establishes a healthy balance of beneficial bacteria and helps control nutrient levels. To cycle your tank, set it up with substrate, decorations, and equipment, and add a source of ammonia, such as fish food or a pure ammonia solution. 

Allow the tank to run for 4-6 weeks while monitoring water parameters until ammonia and nitrite levels drop to zero. Regular water changes and filter maintenance are vital. Perform partial water changes of 20-30% every one to two weeks, removing excess nutrients and debris. 

During water changes, use a gravel vacuum to siphon out debris from the substrate. Clean your filter regularly to prevent the accumulation of organic matter, which can serve as a nutrient source for brown algae.

Manage lighting conditions by ensuring a balanced photoperiod and avoiding excessive light exposure. Different fish and plants have varying light requirements, so research their specific needs and adjust the duration and intensity of lighting accordingly. 

Generally, it is recommended to keep the aquarium lights on for 8-10 hours a day to mimic a natural day-night cycle.

2. Controlling nutrient levels

Monitor and adjust feeding habits to prevent overfeeding, which can lead to excess nutrients in the tank. Feed your fish only what they can consume within a few minutes, removing any uneaten food promptly.

Avoid overstocking your tank. A crowded aquarium generates higher waste levels, which can contribute to algae growth. Follow appropriate stocking guidelines based on the size and species of fish.

Regularly test and manage phosphate and nitrate levels in the water. These nutrients act as fertilizers for algae growth. Utilize test kits to monitor these levels and employ appropriate products or water changes to maintain a healthy balance. Consider using chemical filter media or phosphate removers to help control phosphate levels.

Cleaning and Removal Techniques

When brown algae have already established a presence in your fish tank, it becomes necessary to employ effective cleaning and removal techniques. These methods, when executed properly, can help eliminate existing brown algae and restore the pristine condition of your aquarium.

1. Manual removal

Use a clean cloth or algae scraper to gently scrub affected surfaces. Be cautious not to damage the tank or harm any delicate decorations or plants. You can also use a toothbrush or a soft-bristle brush to reach into crevices and corners where brown algae tend to accumulate.

Pay close attention to hard-to-reach areas, such as the joints of the tank, the substrate, and the edges of the ornaments. Brown algae often cling to these surfaces and can quickly regrow if not adequately removed.

2. Chemical treatments

Algae-specific products are available in the market, such as algae inhibitors or algaecides. These treatments contain chemicals that can effectively combat brown algae. Follow the manufacturer’s instructions carefully and take necessary safety precautions. 

Some chemicals may be harmful to fish, invertebrates, or plants, so it’s essential to select a treatment that is safe for your specific tank inhabitants. Ensure that any chemical treatments you choose are compatible with your tank’s filtration system. 

Some treatments may affect the beneficial bacteria in the filter, disrupting the biological balance of the aquarium. Consider removing activated carbon or other chemical filter media temporarily during treatment to avoid absorption of the treatment chemicals.

3. Biological control methods

Consider introducing algae-eating fish or invertebrates to your tank. Species like Siamese algae eaters, nerite snails, or Amano shrimp can help control brown algae growth by consuming them as a food source. 

However, it’s important to research and selects compatible species that are suitable for your tank size and water parameters. Adding live plants to your aquarium can compete with brown algae for nutrients, ultimately inhibiting their growth. 

Choose hardy aquatic plants that are compatible with your tank conditions. Plants like Java moss, Java fern, and Anubias are known to be resilient and can help absorb excess nutrients from the water column.

Maintaining an Algae-Free Environment

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Once you have successfully eliminated brown algae from your fish tank, it is crucial to implement measures to prevent its recurrence and maintain a clean and algae-free environment.

1. Regular monitoring and maintenance routine

Check water parameters regularly using test kits to ensure they are within the appropriate range for your fish and plants. Test for ammonia, nitrite, nitrate, pH, and phosphate levels. Keep a record of the test results to track any fluctuations or trends.

Perform routine cleaning and algae removal to prevent any potential resurgence. Inspect your tank for signs of algae growth, focusing on areas where algae tend to accumulate, such as the glass, ornaments, and plants. Use a dedicated algae scraper or cloth to remove any visible algae promptly.

2. Consistent adherence to prevention measures

Feed your fish appropriately and avoid overfeeding. Remove any excess food that remains uneaten after a few minutes. Consider using a feeding ring or feeding dish to contain the food and prevent it from dispersing throughout the tank.

Control the duration and intensity of lighting. Adjust the photoperiod based on the needs of your fish and plants, ensuring they receive adequate light without encouraging excessive algae growth. Consider using a timer to automate the lighting schedule and maintain consistency.

3. Seeking professional advice if necessary

If you encounter persistent algae issues or are unsure of the underlying causes, consider consulting with a local aquarium specialist or veterinarian. They can provide valuable insights and guidance tailored to your specific situation. 

They may recommend additional tests or treatments to address any underlying water quality issues or imbalances A professional can help identify any hidden factors contributing to brown algae growth, such as water quality issues, inadequate tank maintenance practices, or specific requirements of your fish and plants.


Brown algae can pose challenges for fish tank enthusiasts, but with the right knowledge and proactive measures, it can be effectively controlled and eliminated.

By understanding the causes of brown algae growth, implementing prevention strategies, and employing appropriate cleaning and removal techniques, you can maintain a clean, vibrant, and algae-free environment for your aquatic companions. 

With consistent maintenance and monitoring, you can enjoy a visually appealing and thriving fish tank that provides a healthy habitat for your fish to flourish. Remember, prevention and regular maintenance are key to keeping brown algae at bay and ensuring the long-term health and beauty of your aquarium.

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