If you have been a die-hard aquarist, we are sure that you might have been aware of the havoc an overgrowth of algae can create in an aquarium. As an aquarist myself for over three years now, I am always disturbed by the growth of algae, which has been a constant issue. Ever wondered how to clean algae from a fish tank? If you follow a few simple tricks and tips, you should be able to handle the algae more effectively in an aquarium.
There are several ways you can clean algae off aquarium. You can remove it using a toothbrush, algae pad or scrubber to clean algae from the fish tank manually. Other methods would include using natural methods such as salt, vinegar, and lemon juice. Keeping an algae-eating fish should be the most useful and practical solution that can yield better results. Brushes can be the right choice to remove algae from fish tank glass.
How to Clean Algae from Your Fish Tank – The Proven Methods
- Algae is normal—but manageable: Most fish tanks develop some algae. The key is consistent cleaning and preventing overgrowth through proper maintenance.
- Manual removal is your first line of defense: Use algae scrubbers, magnetic cleaners, or soft brushes to clean algae in fish tank, from glass, rocks, and décor. Use natural helpers: Add algae-eating snails, shrimp, or fish (like Nerite snails, Otocinclus, or Siamese algae eaters) to support your cleaning routine.
- Control the lighting: Too much light encourages algae. Use a timer and aim for 8–10 hours of aquarium light per day—no direct sunlight!
- Perform regular water changes: Do 20–30% weekly to reduce excess nutrients like nitrates and phosphates that feed algae.
- Avoid overfeeding: Uneaten food breaks down into algae-feeding nutrients. Feed only what your fish can eat in 1–2 minutes.
- Treat stubborn algae carefully: For tough cases, consider safe treatments like hydrogen peroxide, blackout periods, or bleach dips (with caution).
- Prevention is easier than cure: A clean filter, proper lighting, balanced feeding, and live plants go a long way in keeping algae at bay.
Having got a brief idea of how to clean algae from a fish tank, we will now check out the best methods to clean algae from aquarium rocks and decorations.
Use tools for manually removing algae
Manual cleaning of aquarium tanks can be the best way to help you clean algae from the tank. However, to do this, you will need to transfer the fish to another tank and then take up cleaning, if you have delicate fish. Experts from Aquaroum Co Op recommend keeping the fish inside the aquarium when cleaning algae.
An algae scrubber should be the best choice to help clean the walls of your aquarium. Algae can cover the aqauarium glass to such an extent that it can make it extremely difficult for you to see the fish. The algae scrubbers will not damage your glass or acrylic aquarium walls. If any hard-to-reach surfaces contain overgrown algae, you can use a used toothbrush. You can also use an algae siphon to remove the blue-green algae or brown diatom algae. Gravel vacuum siphons are best suited for addressing the algae on the gravel. It is practical to check out scrubbing algae off glass and decorations with melamine sponges or brushes while fish remain in the tank.
Typically speaking, you can use specific tools based on the type of algae that has filled your aquarium. We recommend the use of aquarium-safe tools (magnet scrubbers, algae sponges or a toothbrush) to remove algae without stress.
- Algae Scraper/Pad: Safe on glass/acrylic for cleaning algae from fish tank
- Magnetic Scrubber: Great for glass without getting hands wet.
- Toothbrush: Reach crevices and twist hair algae
- Siphon/Vacuum: Remove algae from gravel (especially diatoms/blue-green algae)
Keep Algae eaters in the tank
Another less toxic and easier method is to keep algae-eating fish in your tank. Of course, make sure not to use a fish that may see other fish in the tank as prey. This option will automatically take care of the future algae growth in the fish tank.
However, this method may not be very effective if your tank has a huge algal growth. That is because these fish will eat a specific type algae and may not touch other types of algae. That apart, they may not be able to reach an entire part of the tank.
If you have a small tank, you can use fish tank cleaning fish like nerite snails, amano shrimp, or a school of otocinclus catfish. For the larger tanks, you can keep larger fish such as bristle nose plecos or Siamese algae eaters. Remember that not every algae eating fish eats all types of algae. You need to specify the right algae fish based on the specific algae type in your aquarium.
Balance the nutrients and lighting
The primary contributors to the growth of algae in the fish tank lie in the left out food and the amount of lighting. Just like the other plants, algae also use the same resources that same resources to grow. Balancing and controlling lighting and nutrients can help you take a good care of the algal growth and clean algae off fish tank.
An increased nitrate level can also contribute to the growth of algae. However, there is no set standard to adjust the nutrients and lighting. You can simply use a trial and error method for the proper adjustment for optimum results. From my personal experience, I would recommend lighting for around 6 hours per day and then adjusting it as per the actual conditions you observe. Aquarium experts recommend 8–10 hours of light per day for planted tanks, using a timer to avoid algae blooms.
As for the nutrients, make sure to adjust it based on the number of tankmates and the eating habits of your fish. I used to feed them three times a day when I first bought an aquarium. Soon, I realized how it was increasing the amount of left-out food and also fish waste, which contributed to the cloudy appearance of the tank. Soon, I switched to a twice-per-day feeding schedule and also reduced the amount of food I added to the tank.
Add live plants
This is yet another excellent option to help you get algae off fish tank and also to clean it off. They will consume nutrients faster, thereby depriving the algae of any food, which can eventually make them die. Some of them are also known to release some algaecide,s which can kill the algae naturally. A planted aquarium is less likely to develop algae growth.
However, if you have a tank with fish that thrive on plants, using live plants in the tank may be out of the question for you. In such situations, you may need to focus on the other means that we have outlined here. I have three goldfish and other fish belonging to the same genre in my tank, and my multiple attempts at using live plants have failed miserably.
Change water frequently
Changing the water at least once every month is desirable to help avoid the growth of algae. Most of us aquarists tend to find water changes tedious and tend to avoid them or postpone them. While frequent water changes can negatively affect the biorhythm in your tank, it is practical to change the water at least once every month. In fact, the standard practice is to do partial changes (e.g. 25% water) at least every 1–2 weeks to control nitrates and organics.
Water changes should not only be just water changes. They should coincide with the complete change, which includes removing the algae and an overall cleaning of the tank. Swell UK recommends water changes to be aimed at reducing the citrates to a level below 40 ppm.
How to Clean Algae from Aquarium Rocks?
After having cleaned the aquarium effectively, it is equally important to clean the aquarium accessories and decorations for an effective removal of algae from it.
Use boiling water
Boil water in a large pot and soak your aquarium decorations in the hot water for around 15 to 20 minutes. If you have plastic parts, avoid soaking them in hot water. Once done, rinse them off under tap water, and that should remove most of the algae.
You can now use an aquarium sponge to remove any algae that may still be sticking to the decorations. Do not use soap and detergents to clean the aquarium decorations.
Use Vinegar
Vinegar is yet another powerful option to remove algae from aquarium decorations. A natural cleaner, vinegar can help you remove germs and algae through a process of oxidation.
Make a solution of three parts of water and one part of vinegar. Soak your decoration in this solution for 15 minutes and rinse it off under tap water.
You can even use lemon juice for the same effect.
How to Remove Algae from Aquarium Plants?
Removing algae from aquarium decorations is quite easy. However, the actual challenge is in cleaning the algae from the plants. They can get damaged if you are not careful. Even artificial plants can be a little difficult to clean without harming or damaging them.
One of the best means to clean the live plants and remove the algal growth on them is to use a slight scrubbing or bleach solution. Of course, the bleach can kill the plants if you are not careful, but then, with that sort of algae growth, the plant is likely to die anyway. Using bleach can be the best last-ditch attempt at saving the plants. If you do not want to take risks, you can use milder methods like hydrogen peroxide dips or long-term “blackout” treatments.
Make a 10 percent bleach solution and soak the plants in it. However, make sure not to soak the plants for more than five minutes. If the plants belong to delicate species, we would advise further reducing the time for soaking it in the bleach solution. Some plants may get damaged by this method, but at least a few will survive.
Prevention would be a better option than this extreme solution. Keep inspecting your plants at regular intervals and shake them off. This will remove any algal growth easily. You can even try rubbing a little to remove the algae from the plants. Use the bleach solution only if the normal methods fail to yield results.
Comparison of Different Algae Cleaning Methods
Check out the table here below to find more details on how different methods work best –
| Method | Best For | Pros | Cons / Warnings | Pro Tip |
|---|---|---|---|---|
| Manual Scrubbing | Glass walls, decor, hard algae | Inexpensive, immediate results | May disturb fish; some sponges can scratch acrylic | Use a magnetic algae cleaner for easy, no-hand cleaning |
| Gravel Vacuuming | Substrate algae, uneaten food, fish waste | Cleans debris & algae in one go | Needs regular use (weekly) | Do during water changes to reduce work |
| Algae-Eater Fish/Shrimp/Snails | Mild algae on plants, rocks, glass | Natural, low-maintenance, fun to watch | Don’t eat all algae types; add bioload | Use Nerite snails or Siamese algae eaters |
| Lighting Control | Excess algae growth prevention | Helps long-term control | Requires timer setup, can stress plants if over-limited | Keep lights on for 8–10 hours/day using a timer |
| Water Changes (20–30%) | Nitrate/phosphate control | Prevents algae buildup, improves fish health | Must be regular (weekly) | Test for nitrate levels to schedule changes effectively |
| Bleach Dip (1:20) | Tough algae on decor or fake plants | Kills algae fast | Dangerous to live plants; rinse thoroughly | Soak no more than 5 mins, then use dechlorinator rinse |
| Hydrogen Peroxide Spot Treatment | Black beard algae, localized outbreaks | Effective, less harsh than bleach | Can harm plants/fish if overdosed | Use a pipette to apply directly to algae during water change |
| Blackout Method (72 hours) | Green water, blue-green algae (cyanobacteria) | Safe for most fish/plants; kills light-loving algae | May affect light-hungry plants | Cover tank fully, no light at all (even room lights) |
The Closing Thoughts
Algae in small quantities can be beneficial for the aquarium and the fish in it. However, an overgrowth of algae can be detrimental to the health of your aquarium life. Opting for the timely options to remove the algal growth can help you achieve better options with your aquarium and the fish in it.
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