6 Best Black Beard Algae Eaters

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The Black Beard algae is the pest of the aquarium world. This tenacious and invasive species of algae is every aquarist’s nightmare for good reasons.

Black Beard algae can quickly overwhelm the tank in optimal conditions, and combating them is rather difficult.

The most obvious solution is introducing some of the algae’s natural predators that would eliminate it progressively.

Today, we will discuss the most popular algae eaters that you should consider for your tank.

While many fish will feed on this species, we will only focus on the 6 most relevant ones.

6 Fish That Eat Black Beard Algae

If you’re dealing with algae overgrowth, relying on fish to contain the problem is sometimes effective and can come with some benefits along the way.

Aside from cleaning the tank and protecting the environment, the fish will also consume the algae for their nutrients. So, you get to shoot two aquatic birds with one stone.

That being said, you should rely on algae-eaters if the algae invasion is in its initial phases.

If the situation is rather severe, the fish might not be too much to contain the spread.

So, let’s look at the 6 best algae eaters to consider:

1. Siamese Algae Eaters

As the name suggests, these fish are professional algae consumers, having the sole role of keeping the tank clean.

They will make for fine additions to any aquatic system that struggles with algae overgrowth.

The fish looks like a 2-colored torpedo with a silver body and a horizontal black stripe traversing it mouth-to-tail. Siamese algae eaters will grow up to 6 inches, so they aren’t exactly tiny.

They are also agile and will move around their habitat a lot, looking for feeding opportunities.

As omnivorous fish, they are easy to satisfy. It would help if you didn’t rely on their propensity for algae to keep themselves satiated.

They also need a well-rounded diet with various foods to get the necessary nutrients to keep them healthy and happy.

Tank Requirements

I recommend at least 20 gallons of space for one Siamese algae eater. This could sound a bit excessive, but these are overly energetic fish that will cover a lot of ground in search of food.

After all, they are considered the best algae eaters in the aquarium business for a reason.

You should also consider having several fish in the same tank, depending on how severe the algae problem is.

More fish will be more effective at dealing with the problem and preventing the algae from reoccurring in the future.

They also like the company of their own species and will form tight groups thanks to their social behavior.

When it comes to water and tank parameters, consider the following:

  • Temperature around 75 to 79 °F
  • Water hardness around 5-20 dGH
  • PH around 6.0 to 8.0
  • A sandy substrate, since these fish will play around the substrate often
  • Shelters and rocky hiding areas, since the Siamese fish like to feel safe in their habitat
  • Plants for better water oxygenation and an environmental look that mimics the fish’s wild habitat

In short, the Siamese algae eaters aren’t too fussy about their habitat, but they do require specific features to keep them comfy and fuzzy.

Difficulty of Keeping – Easy

These are peaceful fish that don’t require much to thrive. Make sure to provide them with a stable setting, peaceful tankmates, and clean waters, and they won’t ask for much else.

Keep in mind that these fish are docile and friendly and don’t exhibit any meaningful territorial or aggressive behavior.

So, you shouldn’t pair them with fish that do. This will stress your Siamese fish, forcing them into hiding and hindering their algae-cleaning abilities.

2. Flying Fox Fish

The Flying Fox is quite similar to the Siamese algae eater in terms of appearance. Both fish have elongated and aquadynamic bodies with one black stripe crossing them from head to tail.

Okay, I guess the Flying Fox has 2 stripes since there’s another one going along the spine, parallel to the side stripe. But that’s where the similarities between these 2 species stop.

From an appearance standpoint, the Flying Fox comes with several other differences, like the coloring, the trademark ‘whiskers’ used to smell the food, and the color pattern.

The Flying Fox has black fins, except for the tail ones, and will come in shades of orange.

Their mouth sensory organs, which look like tiny whiskers, are responsible for the association with a fox.

The ‘flying’ part has no meaning here. Personally, I think the Swimming Fox would’ve made for a more fitting name, but who am I, right?

These fish are quite effective at cleaning the tank of Black Beard algae, especially since they display a pretty expansive bottom-feeding behavior.

They like to remain close to the substrate, but they will roam the entire tank in search of food if they need to.

Tank Requirements

In terms of water and tank conditions, the Flying Fox comes with some rather strict requirements, such as:

  • The temperature at 74-81 °F, which is the ideal range for most tropical fish
  • At least 55 gallons of space for one fish, despite the fish’s medium size (around 5 inches)
  • Stronger water currents to mimic their natural environment’s conditions
  • Water hardness between 5 and 10 dGH
  • A pH between 6.5 to 7.3

It’s worth mentioning that Flying Fox fish are rather sensitive to their water parameters.

They will experience fungal and parasitic infections in poorly maintained tanks, so you should be mindful of that.

Difficulty of Care – Moderate/High

There are several hiccups to consider when getting a Flying Fox:

  • Aggression and territoriality – The Flying Fox, has no time for games. This is an aggressive and territorial fish that will have difficulties adapting to a community tank. Violence is also bound to happen among the Flying Fox’s own ranks due to hierarchical competitivity.
  • Disease susceptibility – The Flying Fox fish are more susceptible to various diseases, unlike most tank fish. Poor water conditions make them vulnerable to fungal and parasitic infections. So, they require intensive maintenance and regular tank cleaning.
  • Antisocial behavior – The Flying Fox doesn’t know how to be a team player. It is extremely territorial and will display antisocial behavior when placed in the same environment with other Flying Fox fish. Males, in particular, are extremely aggressive, so you only need to keep one Flying Fox per tank.

These fish are also notoriously difficult to breed in captivity, so you have that on top of everything else.

Fortunately, they eat Black Beard algae, so that’s worth something.

3. Sailfin Mollies

After discussing the Flying Fox, the Sailfin molly comes to take us to greener pastures.

This fish is friendlier and more docile than the former, making it great for community tanks.

The males will, however, display aggression towards one another, but nothing out of the ordinary. This is common male behavior and should be fairly easy to mitigate with more space, more decorations, proper food, and enough females.

Sailfin mollies are easy to care for. Provide the fish with at least 20 gallons of space and a clean and fresh environment, and they will thrive.

These fish prefer a herbivorous-oriented diet, so they will consume algae from their environment, plant matter, veggies, etc.

However, they will never refuse some mosquito larvae or some animal protein occasionally. Just don’t go overboard with the protein. 2-3 portions per week should suffice.

Tank Requirements

Sailfin mollies aren’t too fussy about their environmental conditions, but they still need certain parameters:

  • Temperature between 75 and 80 °F
  • A lot of open space for swimming
  • Hiding areas like plants and rocks to keep the mollies comfortable

Other than that, whatever applies to regular mollies applies to the Sailfin version as well.

Difficulty of Keeping – Easy

There’s nothing complicated about caring for Sailfin mollies. Provide them with a stable aquatic environment, a balanced diet, and compatible tank mates, and they will thrive.

They are also quite good at controlling the algae population. Just don’t count on their algae-eating behavior to keep themselves satiated.

They still need a balanced diet to remain healthy in the long run.

4. Florida Flagfish

The Florida Flagfish (American Flagfish) is a trademark in the aquarium business for 2 main reasons: it’s a great algae eater and it looks like the American flag.

The fish’s coloring pattern resembles the American flag, combining several colors like red, blue, white, green, and orange.

It also doesn’t hurt that the Flagfish is a docile and peaceful creature that only grows up to 2.5 inches and can adapt to any community setup.

This fish displays no meaningful territorial behavior and can live in larger groups in the right setting.

The minimum group size would consist of at least 6 Flagfish for optimal social dynamics.

The Flagfish is also notoriously hardy and adaptable and can thrive in captivity under the right conditions.

Tank Requirements

The only thing that takes away a bit from the fish is its preference for cold waters.

This means that finding a compatible tankmate requires you to go outside the standard tank fish pool.

The overall tank requirements for the Flagfish include:

  • Temperature around 64 to 72 °F
  • At least 20 gallons of space for a group of 5 fish
  • Water hardness around 6-20 dGH
  • Water pH around 6.2 to 8.2
  • Clean and freshwaters with low movement

A reliable filtration system is necessary to keep the fish’s environment stable and within optimal parameters.

Difficulty of Keeping – Easy

The Flagfish is easy to care for and will thrive in a properly-maintained environment.

Make sure you invest in a heating system as well, despite the fish being a cold-water creature. Temperature fluctuations will affect the fish’s health in the long run.

When it comes to pairing Flagfish with other fish species, consider the Flagfish’s fiery temperament.

This fish isn’t aggressive, but it is kind of energetic and curious. It tends to torpedo through the environment quite often and nip at other fish’s fins.

So, avoid fish like guppies, bettas, and goldfish for these reasons and prioritize danios and tetras.

5. Goodeid Fish

The Goodeid fish is quite an interesting addition to today’s list. These fish are nearly extinct in the wild, and they aren’t exactly too widespread in the aquarium business either.

They are omnivorous, peaceful, and will grow up to 2-3 inches in length. They are also livebearers like guppies and share much of their behavior and water requirements.

Fortunately, these fish are quite voracious and will eat a lot, preferably algae and plant matter.

You can also throw in some protein occasionally to keep their diet diverse and well-balanced.

Tank Requirements

The Goodeid fish isn’t too fussy about its water parameters. In this sense, you should consider:

  • Water temperature around 70 to 78 °F
  • pH around 7.0 to 8.0
  • Water hardness upwards of 10.5 dGH
  • At least 30 gallons of space for several fish

You should have a robust filtration system and a heater in place to provide the fish with optimal living conditions.

This is a rather hardy species, but they need stable and clean waters to thrive.

Difficulty of Keeping – Moderate

The Goodeid fish are easy to maintain and care for, thanks to their adaptable nature. You can keep them in a community set-up, provided you tweak their ranks a bit.

For starters, control the number of males since they can be more aggressive, territorial, and inquisitive.

Then, you should remember not to move the female when pregnant. This will cause stress which could cause the female to miscarry.

Don’t worry, the adults won’t eat the fry. After all, Goodeid fry measure around 0.75 inches at birth, so they can easily handle themselves in an adult-controlled environment.

6. Bristlenose Pleco

This catfish is among the most popular species in the aquarium trade. This bottom-feeder will grow up to 5 inches, consume a lot of algae, and showcase a friendly presence in a community setup.

As a bottom-dweller, the Pleco prefers moderate water currents and a variety of bottom decorations like driftwood and flat rocks.

These will house algae deposits which the Pleco will enjoy thoroughly. The fish’s suction-based mouth will clean the tank of algae-like no other.

This is a herbivorous fish, so make sure you tweak their diet accordingly. And don’t rely on them eating tank algae to remain satiated.

Some sinking flakes and pellets are necessary to keep the Pleco well-nourished and healthy.

Tank Requirements

Plecos are quite adaptable and hardy fish that will thrive in a balanced environment.

The main water parameters include:

  • Temperature around 73 to 81 °F
  • pH around 5.8 to 7.8
  • Water hardness up to 30 dGH
  • At least 20 gallons of space for one specimen

Difficulty of Keeping – Easy

The Bristlenose Pleco is quite undemanding for 3 main reasons:

  • It eats everything it can find within its environment
  • It will adapt easily to any peaceful community setup
  • And it only needs stable water parameters to thrive

Keep in mind that the Pleco needs the right tank layout to remain comfortable and happy.

This is a nocturnal fish, so it requires caves and other hiding areas to take cover during the day. The fish will feed and be more active during nighttime, so provide it with a healthy lighting cycle.

Now, having some good algae-eaters in your tank is naturally a good idea to hinder the growth of Black Beard algae and mitigate the problem a bit.

However, if the algae issue is rather extreme, the algae eaters won’t do much. Black Beard algae won’t change the water’s chemistry, but they will consume nutrients that other plants could use.

They will also block the natural light from reaching the tank’s lower areas, affecting the vegetation and even the fish.

And fully matured Black Beard algae is rather difficult to consume due to the harder tissue. So, what can you reasonably do in this case?

The answer is simple: prevention.

How to Prevent Black Beard Algae in Aquariums?

To prevent Black Beard algae successfully, you must first learn its triggers.

Black Beard algae tends to grow and expand in environments with:

  • Insufficient CO2 – The problem is rather simple. Low CO2 environments hinder the plants’ ability to extract nutrients from the water. The Black Beard algae doesn’t function like that, though. So, the algae will have more nutrients available, boosting their growth and taking over the competition.
  • Too much water nitrate – Nitrates are a food source for plants and some bacteria in the tank. In a way, nitrates are essential to any aquatic environment to create a necessary chemical and nutritional balance. The problem occurs when there are too many nitrates in the water. Such an environment will create the ideal conditions for the Black Beard algae to thrive.
  • Too much lighting – Algae need light to grow and thrive, whether natural or LED-based. Many people will provide their fish with excessive lighting, and they don’t need that. Most fish will only get moderate lighting in their natural environment, so make sure you dial the LEDs down a bit.

So, knowing all these problems, what should you do to prevent the excessive buildup of Black Beard algae in your tank?

I would say you have a handful of methods to stick to:

  • Keep the water clean – Eliminate fish waste, dead plants, dead fish, and any other decaying matter that could alter the water chemistry. This will prevent the buildup of nitrates and effectively prevent the optimal conditions for the algae to spread.
  • Control the lighting – Most fish only require modest lighting. Aquarists light up their tanks excessively for aesthetic reasons, not because the fish need it. Keep the lighting low, and you will prevent the conditions that would support algae buildup.
  • Have some reliable alga-eaters around – It never hurts having several algae eaters in the environment, especially in a community setup. The fish will consume the Black Beard algae before it matures, effectively preventing the organism from taking over the tank.
  • Boost CO2 levels – This technique is great at preventing and countering algae overgrowth. Having more CO2 in the water will provide the plants with more nutrients, starving the algae and hindering their development greatly.
  • Perform regular cleaning – Black Beard algae are clearly visible due to their distinct look. If your tank shows signs of algae development, tweak the maintenance routine a bit. This will allow you to eliminate the algae and prevent them from taking over.

The main point to take with you today is that algae eaters don’t make for a silver bullet. While these fish are effective at containing the algae’s spread, they can’t do much against matured algae with harder tissues.

Instead, you should use a combination of methods to attack the Black Beard algae from all sides.

The goal is to prevent their development and takeover of the tank in the first place.


Black Beard algae are a true pest of any close aquatic setup. They are rather difficult to remove and will ruin the tank’s aesthetics.

They will also hurt the vegetation and, eventually, the fish by suffocating the environment.

In the ideal conditions, Black Beard algae will spread throughout the tank, covering any surface they come into contact with.

Fortunately, you now have reliable means to counter them and prevent their formation in the first place.

Author Image Fabian
I’m Fabian, aquarium fish breeder and founder of this website. I’ve been keeping fish, since I was a kid. On this blog, I share a lot of information about the aquarium hobby and various fish species that I like. Please leave a comment if you have any question.
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