Aquarium Algae Control, removal, and prevention in Fish Tanks

Aquarium algae control is one of the most frequently discussed topics by people who have fish tanks. Indeed, the control, removal, and prevention of overgrowing aquarium algae is quite tricky for many fish keepers. To solve the algae problem, we must first understand what it is and how it grows.

Algae, a simple low life form of organism exists almost anywhere with water. If you own a fish tank or pond, you will definitely encounter the algae problem at some point whether you like it or not. When it appears in your aquarium, you might experience green water, or green glass, or hair like “plants” in your fish tank. Algae problems like green water and green glass can lower the visibility of objects inside the fish tank, which make it less enjoyable to look at your beautiful fish. Algae can be extremely annoying for planted aquariums, where it can cover up your aquarium plants and block the light. This can result in the plants being unhealthy or even dying.

When algae control had failed, an algae boom turned the aquarium water green


When Algae Control failed

While some people might try to keep a small amount of controllable algae at certain spots in their fish tanks, such as on the rocks, driftwood or other decorations for a more natural looking aquarium, most fish keepers simply want to get rid of algae.

Where did algae come from?
Algae will always exist in the water, even in the tap water. The water treatment process kills almost all algae before sending the water to your home through the pipelines, but all it takes is a single cell algae to start multiplying under the ideal conditions. It means the algae in your aquarium can come from the tap water. It can also come with the water you get your fish or aquatic plants. e.g., the fish store.

How do we control the growth of algae in a fish tank?
In order to get rid of algae, we must first understand how it grows. While there are many species of algae, they all have simple cellular structures. Some algae are single-celled, while others are multi-cellular. They are not as complex as the real plants even though people used to think they are plants. Real plants have different cells functioning as different “organs”. Algae mostly have only a single type of cells.

However, just like real plants, algae need necessary nutrients in the water and sufficient light source in order to grow. They feed mostly on nitrate and phosphate in the fish tanks. Nitrate is the final product of aquarium nitrogen cycle. Anything that produces ammonia will result in nitrate in a well cycled aquarium. Phosphate is another important substance that algae need for their growth. It mostly comes from breaking down fish waste, and leftover fish food, as well as decaying plants, or dead fish.

Most algae species are purely photosynthetic just like plants. They absorb CO2 and lights while producing Oxygen. Without lights, they can’t produce their own food source, and will die.

Go for the Source of Algae Boom
In order to control the growth of algae, we must find the cause. Usually an algae boom indicates excessive lights, nitrate, and phosphate.

Too much Light
It is extremely important that an aquarium must not be located near a window where it can be exposed to direct sunlight. This part is mentioned in The Location to Set up a Home Aquarium. If the aquarium has its own light source, it is highly recommended to use an automatic timer to automatically turn the lights on for only 8~10 hours a day. Even for a planted aquarium, we do not recommend more than 12 hours of light exposure each day.

Too Much Nutrients
To limit the amount of available nitrate and phosphate in the aquarium water, the fish must not be overfed. All leftover fish food requires to be removed immediately via fish net or an aquarium vacuum. Weekly maintenance of 30~50% partial water change along with substrate vacuuming is required to keep nitrate and phosphate level low

Limiting the light exposure and lowering the nutrients concentration for your fish tank can avoid algae boom, but it will not avoid algae all together. What should we do if there is still algae in the tank?

We highly recommend avoiding any chemical means to kill algae. Many of the algae control chemical products can harm your fish and plants, and sometimes it can even kill them. To be on the safe side, stick to the natural algae controlling methods.

Natural Ways for Algae Control

Algae Control through Physical Removal
You can definitely remove algae manually. For the green water problem, large partial water change will certainly remove large amount of algea. For algae growing on the sides of the glass, using an algae scraper will clean it up nicely. For hair like algae, just use your hands to pull it off. There is no need to be nice to them. If algae are growing on your plants and hard to be removed, cut the part of the plants covered with algae and throw it away. While physically removing algae will never completely eradicate the problem, it will temporary reduce algae to a much lower level.

Algae Control Through Algae Eating Animals
1. Algae eating fish
There are many species of algae eating fish, shrimp, snails available for aquariums. While many fish species will more or less eat some algae, the best are referred to as “algae eater.” Good algae eaters include, but not limited to, Otocinclus catfish, Bristlenose, gold barb, Garra, Siamese Algae Eater, American Flagfish, and Black Molly.

2. Algae Eating Shrimp
Many species of popular aquarium shrimp eat algae. The best species is the Amano Shrimp. Dwarf shrimp species such as Red Cherry shrimp or Yellow shrimp and Crystal Red shrimp will also eat algae, and they are easy to take care of and can be a very good addition to your aquarium.

3. Algae Eating Snails
Ramshorn snails, Malaysia Trumpet snails, and Zebra Nerite snails are some of the most commonly used algae eating snails. My favorite is the Zebra Nerite snail, because these snails are not only beautiful, but they will not breed at all in freshwater. Thus they will not overpopulate your aquarium and become a pest snail.

A combination of algae eating fish, shrimp, and snails will do a good job controlling the algae in your aquarium. You must understand that algae control is not algae eradication. You should never rely only on the algae eaters. They will help, but not a cure-it-all solution by itself.

Natural Competitors for Algae Control
Since the algae is a simple form of life, it can be out-competed by real aquatic plants if the plants are given what they need. CO2 injection is a good way to boost plants’ competitiveness. With more CO2, plants will start to absorb large amount of nutrients from the water and at the same time it will starve the algae. This method only works for heavily planted aquariums.

You have to remember there will always be algae in the water because you can never eradicate algae completely. Even if you can’t see it, it will still “boom” if the conditions are “right.” Keeping your aquarium well maintained along with a good cleaning crew will keep the algae in control.


2 thoughts on “Aquarium Algae Control, removal, and prevention in Fish Tanks

  1. Are plecostomus a good fish to control algae in my fish tank? It’s a size 13 fish tank. Plus my algae is brown is that normal?

    • Not really. Pleco is too big for most fish tanks. You should not relay on the fish to control the algae. They can only help so much. To control algae, like the article said you must not giving the algae the right condition to multiply.

Leave a Reply

Your email address will not be published. Required fields are marked *


*