How To Keep Algae Out Of Betta Tank

Last Updated on October 6, 2020

Algae buildup is an issue that fish keepers deal with at some point or another. A little green algae growth on rocks and driftwood isn’t a bad thing. It makes your tank look more natural. However, extreme green or brown algae buildup on the glass of your aquarium is not a delightful sight to see.

Algae growth is a natural occurrence in fish habitats. When confronted with an algal infestation, many aquarium keepers give up their beautiful hobby. Do not lose hope if your fish tank has algae because there are solutions. You can limit the level of algae growth inside your betta fish tank by practicing good tank maintenance habits.

Types of Algae

Common Brown Algae

Brown spot algae, also known as diatoms (Bacillariophyceae), will grow on decorations, on plants, and even on the glass. Soft and slimy brown algae typically found on the substrate first, slightly filamentous, can grow even in dark tanks. You can dislodge these from surfaces with a quick wipe. The fluctuation of water parameters encourages their growth.

Common Green algae

Green spot algae (probably almost always species of the Coleochaete family) are hard green spots that coat glass, live plants, and decorations. They are a little tougher to get rid of and you need to scrape them away.

Green dust algae are soft green algae that coat the glass and substrate of the aquarium but do not form filaments.

The free-floating algae Chlorella turns all the water in the aquarium bright green and opaque.

Green hair algae Oedogonium is another common algae that grow in aquariums. It is light green and can be in different shapes like strands, networks of stems, or a hairy appearance. They are easy to get rid of but can return just as quickly. The long filaments are tough and not very attractive to algae eaters. It is, however, easy to remove with a toothbrush, mostly.

Black beard algae (BBA) / Brush algae

Black beard algae (BBA) or brush algae (Audouinella sp., Rhodochorton sp.) belong to the group of red algae, just like staghorn algae Their natural color is not red, though, but varies from dark green over gray to a deep black. However, if you put these in alcohol, they will turn reddish. This is easy proof that the algae you’re dealing with are actually red algae.

These cling stubbornly to the ground they grow on, like technical equipment, the leaf margins of aquatic plants, aquarium decoration, or even grains of the substrate. The tufts look like a beard or a brush, and that’s where the name comes from.

These will grow on the leaf edges of your plants that are the slowest growing. They develop in clumps or patches varying from black to red. Shoot tufts that are dark brown or black, difficult to remove manually.

Blue-Green Algae

Technically not really algae, they are cyanobacteria (blue bacteria), but you can treat them the same way as algae in your tank. They are a slimy type of mossy substance that can quickly overtake the substrate, especially where the glass meets the gravel. It forms “mats” on the surface of plants and substrate. Most commonly dark emerald green, but can also be red or brown. It also has a distinct smell to them.

Staghorn Algae

Staghorn algae (Compsopogon sp.) belong to the group of red algae. They are easy to diagnose as their growth habit looks like the horns of a stag. They show different shades of gray. If you immerse a piece of these in alcohol, it will assume a red color.

We usually find staghorn algae on aquarium decoration, technical equipment, and the margins of the leaves of aquatic plants. They are hard to remove manually and seem to be unattractive for most algae-eating aquarium animals.

Reasons Why Algae Appears in Your Tank

  1. Algae primarily grow when there is excess phosphate or nitrate building up in your aquarium. Overfeeding increases these substances. In a planted aquarium, healthy plants consume and remove these nutrients from the water. It is a symptom of a nutrient imbalance or buildup in your tank. Addressing this will cause the algae to stop growing and die off. Directly killing off the algae (using an algaecide) is only a temporary solution if we do not deal with the underlying issue.
  2. We leave the lights on for longer than is necessary for the plants’ needs. Light is the number one source of energy for algae. Without light, it will not grow. Natural sunlight directly on your fish tank will be a major cause of algae growth. Monitor and time photoperiods to keep the algae from developing.
  3. Poor water parameters because of lack of maintenance also contribute to the appearance of algae. Most nutritional imbalances cause increased algal growth. Our slacking tank maintenance such as if we skip regular water changes contributes to this. A weekly water change of around 20-50% is vital for the overall development of an aquarium, and it may prevent algae. Besides the addition of fresh, unpolluted water, by changing the water you remove unwanted substances and prevent certain elements from building up in the water. A water change will keep the nutrients for your plants at a suitable level.

Different Ways How To Keep Algae Out Of Betta Tank

Different Ways How To Keep Algae Out Of Betta Tank


We can use razor blades to scrape the glass. Here are a few products available online to help you with your glass scraping needs.

Best algae scrapers

SLSON Double Sided Sponge Brush Cleaner

Aquarium algae brush made of high-quality sponge which could make algae removal quick and effective. Brush handle made of premium plastic, sturdy and durable. Has a non-slip handle surface. Suitable only for glass fish tanks. It is not suitable for plastic and acrylic fish tanks. Designed with a hole at the end of the handle for convenient hanging and storage. Rinse with fresh clean water before and after use.

SLSON Stainless Steel Scraper Cleaner

These scraper blades have a unique right-angle design which could remove buildup completely with no residue. Can clean the tank corners and avoid scratching of glass surfaces.

The scraper material is high-quality stainless steel which makes it strong and durable. The surface is resistant to rust or corrosion. It comes with 10 pieces of right-angle blades.

The cleaner comes in with two bonus handles approximately 25 inches in length. This product is only suitable for glass aquariums. It will scratch tanks made of acrylic.

Do not use it on dry surfaces. Rinse pad with tap water before and after each use. Do not use it in high concentration saltwater, saltwater contains chlorine, which is corrosive to metals, including stainless steel. Please keep it away from children as the blade is sharp.

Kent Marine Pro-Scraper II

Corrosion-resistant fiberglass makes up a durable construction-handle. An extendable cleaning tool has an easy to adjust handle length feature done with a simple twist. The Kent Marine Pro Scraper comes with three interchangeable blades; one steel, one plastic, and one green felt. They made the green felt blade for scraping algae on acrylic tank surfaces. Use the plastic blade for removing algae on acrylic surfaces with no problems. We should use the steel blade on glass surfaces only. The Pro Scraper heads and blades are interchangeable and replaceable.


You can use bleach to clean aquarium decorations, which have extensive algae accumulation. Prepare a bleach soak that comprises 10% bleach in a specified amount of water. Soak the items for about 15 to 30 minutes. Scrub off as much grime as you can. Rinse them off very well under running water and let them out to dry before returning into the fish tank.

Glass Cleaner

Use a safe glass cleaner when cleaning the outside of your aquarium. Once you clean the inside of the aquarium, do the hood, light, tank top, and outside glass next. Regular glass cleaners contain ammonia, which is toxic to fish. Standard lime cleaners are even more toxic.

For better results, use vinegar or a cleaner designated as aquarium safe, and make sure you rinse the surfaces with a clean damp cloth.

Water Siphon

You should clean the gravel/substrate of your tank when doing weekly maintenance. There are different aquarium siphon brands available, all of which work essentially the same. From manually operated to automated, pick the one that fits your requirements and budget.

Aquarium gravel vacuums or water siphons suck up water with the detritus from the substrate. Use these to vacuum away debris on the substrate. The gravel vacuum should stir up the gravel and remove debris without sucking up the gravel. Be sure to vacuum the entire surface of the gravel thoroughly so you remove all debris. Go through the entire substrate of the tank and siphon gravel until water is almost clear.

Water Changes

Regular maintenance of your betta fish tank is a must for any betta enthusiast. This is a responsibility that we should not avoid. Water changes are very important in the battle against algae proliferation.

Do partial water change of 20-30% weekly. Replace it with clean fresh water treated with a water conditioner. It’s not a good idea to take more water out because this may alter the water parameters of your betta fish tank.

Water changes will prevent the buildup of too many harmful substances such as ammonia, nitrite, and nitrate. This will also replenish minerals needed by your betta fish. Keeping good water parameters will be one of your best weapons against algae growth.

Filter Maintenance

Keep your filter media in excellent condition by cleaning it once a month. Filter media contains beneficial bacteria responsible for keeping the nitrogen cycle established in your tank. Rinse out debris using tank water. Squeeze out sponges in a bucket with tank water until the water coming from the sponges are more or less clear. Do not use tap water to clean your filter.

Light Control

Only switch on the lights for six hours in the beginning. When the biological system in the tank runs stable and without problems, you may increase the daily lighting time by half an hour per week. Under moderate to strong light, you are aiming for a daily lighting time of 8 to 10 hours, under less powerful light, a longer phase of 10 to 12 hours is recommendable.

Some fish keepers perform a complete tank blackout for around four days. Turn off all lights and wrap the tank in something dark so that light can’t get in. Do this to starve the algae of light.


Algaecides are chemicals that suffocate or destroy the algae present in your tank.

This should only be a last resort. We cannot perform it too many times because it will destroy the beneficial bacteria established in your fish tank. This will cause the tank to re-cycle.

These come in different types like liquids, powders, or tablets. Algaecide can destroy plants and kill invertebrates. It is a quick solution, but not a permanent one. You still need to tackle the root of the problem which is the imbalance of nutrients.

UV Sterilizers

A UV sterilizer works by penetrating and breaking down the algae cell wall, allowing them to adhere to each other. This causes the algae to flocculate, or clump together, enabling the filter to remove it from the water. This will help to diminish and to keep away the unwanted green algae from your water.

High-intensity UV light sterilizes the bacteria and microorganisms present in the water by breaking their cell membranes or damaging their DNA or other organelles in the cells.

Ultraviolet sterilizers can help reduce the spread of free-floating algae. While it will kill algal blooms, it will not totally eradicate them. A UV sterilizer is not a replacement for a good biological and mechanical filter, which is still necessary to filter out algae from the water.

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