When I first started out in the aquarium hobby, I didn’t have enough resources to guide me. All I had was occasional advice from the aquarium shop and a lot of guesswork. That’s why I’d often watch the water change its color from clear to pea soup in a matter of a few weeks, wondering what I did wrong.
After years of trials and errors, I’ve finally mastered the do’s and don’ts to prevent it.
So, I’ve brought you a 101 guide on algae and everything you need to know about it. But first, let’s start with the most daunting challenge—how to get rid of algae in an aquarium?
How To Get Rid Of Algae In An Aquarium?
Algae outbreaks in aquariums are common occurrences and the reasons can be many.
Stocking certain species of algae-eating fish and shrimps like Yellow Tangs and Amano Shrimps can help you get rid of algae to an extent.
Live plants also hinder the algae growth as they will directly compete for light and nutrients.
Other factors like light settings, filtration system, phosphate level, and water quality also play crucial roles when it comes to getting rid of algae in an aquarium.
Stock Live Plants In The Tank
Yes, beating algae in its own game. Stocking live plants is one of the most constructive ways of getting rid of algae in an aquarium.
Plants will directly rival algae for nutrients and light and win most of the time. Thus, the lesser the nutrients floating in the water, the lesser will be the algae bloom.
Submerged plants like hornwort, anacharis, and parrot’s feather are your best bet when it comes to shading light and taking up additional nutrients to keep algae at bay.
Floating aquarium plants, like duckweed and amazon frogbit, are a close second. They can effectively spread out to block the shade while soaking up all the excess phosphate and nitrite.
Stock Algae-Feeding Shrimp
Here’s a tip straight from the father of modern-day aqua scaping—Takashi Amano.
Amano first experimented with using Yamato Numa shrimp in his planted tanks in the 1990s.
And oh boy, did he succeed. His method basically revolutionized how to get rid of algae in an aquarium tank.
Currently named Amano shrimp (scientific name: Caridina multidentate), this transparent and peaceful creature can eat algae throughout the day while not harming the plants.
These industrial aquarium cleaners will even clean your sand and gravel.
Stock Algae-Feeding Fish
Like Amano shrimp, a few algae-eating fish species will get the job done for you.
The most common is the Bristlenose Pleco, which will only grow about 4 inches long. Thus, they are perfect for medium-sized tanks.
However, plecos are very territorial around each other. Make sure you only keep one in a tank.
Other suckermouths like Common Pleco can get quite big, growing anywhere between 12-24 inches. So, they’re only suitable for big tanks.
Some other algae-eating powerhouses include Siamese Algae Eater, Chinese Algae Eater, and Live-bearers.
However, when choosing an algae-eating fish, don’t forget to consider these points:
- Water flow’s speed
- Foliage’s density
- Aggression level of tank’s habitats
- Oxygenation level
Tweak The Lighting Settings
Algae can reproduce prolifically in bright environments. That’s why it’s essential to mimic the day/night light schedule in your tank and stick to it. You can simply turn them on in the morning and off before you go bed at night.
Buying a timer can be the right choice as you don’t have to worry about turning the lights on and off every day. For regular aquariums, 6-10 hours of daily light is enough, while a planted tank will need anywhere between 10-14 hours.
Tip: It’s best to replace the bulbs yearly. The loss of spectrum and intensity in old aquarium bulbs will create a favorable environment for algae growth.
If the natural methods haven’t yielded the results you wanted, using algae treatments, also known as an algaecide, can be your last resort. I personally have used it only once, as I’m not a fan of adding chemicals to the fish tank.
If you’ve decided to use algae treatments, make sure to consult with the seller and precisely follow the instructions.
Here are five tips to follow:
- Don’t use an algaecide in aquariums that were set up less than three months ago
- Don’t go overboard than the quantity recommended
- Make sure the water is filtered and oxygenated enough to compensate for sudden algae death
- Don’t use in tanks with invertebrates or crustaceans like crayfish, shrimps, and crabs
- Scrape off as many algae as possible beforehand to ensure maximum effectiveness
If you’re looking for a quality scrubber, this one by QANVEE does a very decent job.
Phosphate naturally occurs in the tank when the waste is broken down. On top of that, everything from fish food to chemicals used to bovver water contains phosphate. And increment in phosphate level will only boost algae growth.
You can use phosphate removers, usually available in a granular format, to curb this problem.
Secure the phosphate remover in a filter bag and place it near the filter area with good water flow. It will then absorb the phosphate lock it away.
However, since its capacity is limited, you need to replace it a few times.
Here’s a phosphate remover by API:
Switch To RO Water from Tap Water
Before you actively look for solutions to getting rid of algae in an aquarium, make sure to do a water test.
Tap water often contains algae-fueling fertilizers like phosphate and nitrites. So, suppose the test result shows higher phosphates and other algae-inducing elements.
In that case, you’ll want to switch to RO (reverse osmosis) water. For this, you’ll need a RO unit or a tap water filter that needs to be fitted in the faucet.
Boost Your Filtration System
The filtration media you use will make a big difference in algae growth in the tank.
For example, using phosphate-controlling media and biological boosters will eliminate the phosphate levels, discouraging algae growth.
You can also find carbon-phosphate removers that will keep your water clean and transparent while removing dissolved organics that algae feed on at the same time.
Lastly, don’t forget to change the chemical and mechanical media every month. Once they’re exhausted and saturated, they’ll leach the pollutants back into the tank!
Yep, this one definitely has to be on the ‘how to get rid of algae in an aquarium list,’ right? The good, old hands to the rescue.
The easiest and most reliable way to remove the algae is using an algae scrubber. The scrubbers have a rough side designed to scrub away the stubborn algae growth and a sharp edge to scrape it away.
For really persistent algae, you may need to use a razor blade. Be careful! Lots of bacteria down there to infect a potential wound.
Don’t Overfeed The Fish
As a child, I fondly remember marveling at the scene of fish coming to the surface to gobble up the feed as soon as my mother poured it in.
Sometimes, I’d give the fish food at random times just to watch them eat. If you’re someone like me, you’re probably guilty of overfeeding your fish.
But do you know overfeeding is one of the most common reasons behind algae growth? Algae feed off on both fish waste and uneaten food floating on the surface—a double whammy.
Now that you know all the tried and tested algae control methods let’s dive into the specific details.
The Most Common Algae Types in Aquarium and the Easiest Way to Remove Them
In the end, how to get rid of algae in an aquarium boils down to what kind of algae it is. Here are the six usual culprits, their causes, and tips on how to fight them.
Brown Diatom Algae
In appearance, brown diatom algae look like a thick, dusty layer covering the aquarium walls, substrate, and other surfaces. It can even thrive in a low-light setting if chemical food is available.
Initially, brown diatom algae will begin with a thin dust-like substrate in the aquarium. It will manifest into a thick slim film covering everything from glass, plants, and substrates in about a week.
What Causes The Growth Of Brown Diatom Algae In An Aquarium?
Here are the main reasons behind the growth of brown diatom algae in tanks:
- Excess levels of nitrates, silicates, and phosphorus in the water
- Inadequate lighting since this kind of algae thrives in low light
- The buildup of dead material and uneaten food, which fuels the nitrates level in the tank
- New tanks during the nitrogen cycle don’t have enough time to age filter and substrate
How To Get Rid Of Brown Diatom Algae In An Aquarium?
In texture, brown diatom algae are quite soft and don’t adhere firmly to the glass. Thus, it can rub off easily. Use a vacuum to remove the algae before using a soft cloth to clean the tank.
Algae eaters like shrimp, snails, and Otocinclus catfish love to feed on it. Similarly, adjust the light settings if it’s set too low.
Lastly, if you want to completely eliminate its nutrient sources, you can use phosphate/silicate remover as well.
Best Brown Algae Eaters
- Nerite Snails
- Yellow Tangs
Blanketweed—also called a filament, strong, or thread algae—refers to various filamentous algae.
The unsightly blanket weed proliferates quickly. It can form thick green masses floating freely on the surface or entangle the tank’s plants, wood, and gravel. Its growth will become uncontrollable if not intervened in time.
What Causes The Growth Of Blanket Weed In An Aquarium?
Here are the main reasons behind the growth of brown diatom algae in tanks:
- High pH level in the tank, anything exceeding 8.5, creates a suitable environment for blanket weed
- Excess of nitrates, Co2, and light in the tank
- Poor-quality plants from the same algae family, like Marimo Balls, can trigger the outbreak
How To Get Rid Of Black Weed In An Aquarium?
Black weed is very stubborn and not easy at all to remove. On top of that, it produces a pungent smell when scraped.
Since blanket weed blooms in alkaline water, you can add doses of glutaraldehyde-based carbon supplements to the water.
For manual scraping, follow these steps:
- First of all, turn off the water current in your tank
- Next, fetch your long tweezers and pick out as much as you can
- Finally, use bioavailable carbon like Excel with a syringe for spot treatment
Best Blanket Weed Eater
- Amano Shrimp
- Cherry Shrimp
- Grass Carp
- Koi Fish
Black Brush Algae
By far, black brush algae (BBA) are the most problematic algae I’ve run into in my fish keeping experience. As the name suggests, it grows in dense, bushy clumps—growing on plants, décor, and driftwood.
It is soft and slippery but quite challenging to remove. BBA produces a red-light protein called phycoerythrin that gives it a dark color.
What Causes The Growth Of Black Brush Algae In An Aquarium?
Here are the main reasons behind the growth of black brush algae in tanks:
- Brightly-lit environments promote the growth of this kind of algae
- High level of organic pollution resulting from overfeeding
- A buildup of muck in the filter and substrate
- Inconsistent or low Co2 levels
How To Get Rid of Black Brush Algae In An Aquarium?
Algae-eating species can help you get rid of BBA if the outbreak is mild.
However, if it has become rampant, you may need to resort to chemical treatments like spraying liquid carbon directly on the growth area. Before that, use some elbow grease to remove the algae. That will make the treatment more effective.
Note: You need to very careful and precise as some plants, such as Vallisneria, are quite sensitive to liquid carbon.
Best Black Brush Algae Eater
- Siamese algae-eater
- Florida Flagfish
- Twig catfish
- Black Molly
Minnesota Pollution Control Agency (MPCA) states that blue-green algae aren’t actually algae but a type of bacteria called cyanobacteria.
Blue-green algae flourish the best in warm, nutrient-rich water bodies and manifest into big blooms. It has a soft and slimy texture and an interesting earthy smell. It usually grows on the substrate and the glass, where it is exposed to light the most.
What Causes The Growth Of Blue-Green Algae In An Aquarium?
Here are the main reasons behind the growth of blue-green algae in tanks:
- Bright light settings and a high level of organic nutrients in the water
- Newly set up tanks during the break-in period can’t fight algae bloom
- Low water circulation in the tank
How To Get Rid Of Blue-Green Algae In An Aquarium?
MPCA doesn’t recommend using chemical treatments to get rid of blue-green algae. That may kill the algae successfully, but toxins contained in their cells will be released into the water at once.
You can try this technique instead.
Step 1: Remove as much BGA as you can manually and change about 50% of the water.
Step 2: Test the level of nitrate. 20ppm is generally what’s required for fish tanks. If it’s below that, add potassium nitrate.
Step 3: Increase water circulation to prevent idle spots and add airs stones.
Step 4: Turn off the aquarium lights and cover it for 3-4 days (fish can easily go from 3-7 days without food).
Step 5: Perform another 50% water change.
Step 6: Take out the air stones.
Best Blue Green Algae Eater
Algae eaters don’t prefer feeding on this type of algae. So, don’t count on them for this matter.
Green Water Algae
Green Water Algae is not harmful to the fish. But it’s a downright eyesore to look at, don’t you think?
Actually, many fish and plants live perfectly under green water algae in their natural habitat. But it doesn’t mean you need to keep a tank the color of pea soup.
Green water algae outbreak is caused by the explosive growth of single-called green planktonic algae. Once the nutrient level in the tank depletes, these can disappear as quickly as they appear.
However, that’s not exactly good. A sudden disappearance will lower oxygen levels, which can be fatal to your fish.
What Causes The Growth Of Green Water Algae In An Aquarium?
Here are the main reasons behind the growth of green water algae in tanks:
- The light is set too bright, or your tank is exposed to direct light from the sun
- Nutritional imbalance in planted tanks
- Often occurs during the cycling phase of a newly set tank
- Spike in ammonia level in the water
How To Get Rid Of Green Water Algae In An Aquarium?
As green water algae are made up of single-celled organisms, regular water changes won’t work.
Even if you change 99.99% of the water, few organisms will still be left in the tank. They’ll reproduce quickly and change the water’s color to green once again in a matter of no time.
Instead, what you’ll need is a UV sterilizer that can cure the problem within a span of two weeks. You can also use the blackout method and deprive the tank of any light for a week or so.
However, that can be quite harsh to your aquarium’s plants and fish. So, it’s better to go with a UV sterilizer.
Best Green Water Algae Eater
- Siamese algae eater
Hair algae, also called fuzz or thread algae, is a filamentous algae species that grows in long yet soft and loose threads.
These algae are notorious for clinging on plants, decorations, and even gravel of the aquarium. When taken out of the water, hair algae feel and behave exactly like hair—hence, the name.
These grow super-fast and are quite stubborn, too.
What Causes The Growth Of Hair/Fuzz Algae In An Aquarium?
Here are the main reasons behind the growth of hair/fuzz algae in tanks:
- A combination of high nutrient level in the water and slow-growing aquatic plants
- Bright light sources or direct sunlight
- A deficit of nitrate and CO2 in water
- High level of phosphate in water
How To Get Rid Of Hair/Fuzz Algae In An Aquarium?
Once again, the best way to remove hair algae is by using your two hands. Since these algae leech on the plants, you’ll have to hold down the plants with one hand remove algae with another. You can also twist it around a skewer with a rough surface (like a toothbrush) and pull it out.
Similarly, turn off the aquarium lights at night to replicate the day/night cycle. Lastly, there are lots of algae eaters that love to nibble on hair algae. Thus, stocking one or two of them might go a long way.
Best Hair/Fuzz Algae Eater
- Florida Flagfish
- Amano Shrimp
- Siamese algae eater
- Red Fire Shrimp
Conclusion: How to Get Rid of Algae in an Aquarium?
There are approximately 6000-8000 green algae species in the world – 90% is freshwater and 10% is marine.
In this blog, I shared 10 tips on how to get rid of algae in an aquarium and tried to shed light on the 6 most common types of algae. That should pretty much cover what we hobby aquarists should know.
As fish keepers, it’s crucial to understand that we’re not in a battle against algae—just like a squeaky-clean water tank isn’t always the best.
If there’s a small algae patch forming on the driftwood or rocks, don’t panic. In fact, algae intake excess nutrients while producing oxygen for your tank. See, it’s not all vices.
However, if it starts covering the glass, substrate, or plants, that’s when you need to take action.
Anyway, remember, it’s all about finding a balance in your tank’s ecosystem for a healthy and thriving fish tank.