Some people dread having algae, while others welcome it into their tanks. Like it or not, algae is part of your aquarium. Given the proper conditions, algae will flourish and can even be considered a sign of a healthy aquarium.
What is Algae? The complete answer to that question is beyond the scope of this article. For our purposes, algae is a photosynthetic organism that needs light, water and nutrients to prosper, elements which are readily available in an aquarium. Eliminating it from your aquarium would be practically impossible. Knowing that, controlling and even utilizing algae should be your goal.
When algae is in balance, meaning it is in small quantities, it is a sign of good water quality and can be controlled through regular maintenance or by being eaten by your fish. When algae is out of control, it can be an indicator of poor water quality or simply be unsightly, detracting from the aesthetics of your aquarium.
Aside from water, which is a given in an aquarium, light and nutrient levels contribute to the growth of algae. The longer and more intense the light, the more algae growth you will have in your tank, provided other required nutrients are available. Phosphates and nitrates are the nutrients that will contribute to algae growth. Phosphates enter your aquarium through tap water and other aquarium additives, including certain brands of carbon. Nitrates are the result of the breakdown of fish and plant waste, and can also be found in tap water.
Brown Algae (Diatoms) — This is the first type of algae that begins growing in a new aquarium. It usually grows on the gravel and glass. Unlike other types of algae, this type requires silicates in order to grow. By increasing light levels, this type of algae can be replaced by the more beneficial green algae. Brown algae can easily be scraped off the glass. Herbivorous African cichlids generally have little to no interest in this type of algae as an easy meal.
Green Algae — Usually the most common type of algae, green algae is a positive indicator of good water conditions. Herbivorous fish like Malawi Mbuna will eat it readily. Reducing the amount of light and sources of nitrates will help control a green algae outbreak. This type of algae can lead to algae blooms that turn the water green as a result of too much light or direct sun light.
Red Brush Algae — Occurs in water ideal for African cichlids: high in pH and KH. To get rid of this type of algae, you need to scrape it off or soak decorations in a light bleach solution. As a last resort, copper can be used to treat the tank.
Slime/Blue-Green Algae — Unsightly and dangerous to planted aquariums. Generally indicates poor water quality with high levels of phosphates and nitrates. Frequent water changes will help eliminate this type of algae. As long as poor water conditions continue, this type of algae will return.
Hair Algae — Light green in color and can reach lengths of over 1 inch. Certain herbivorous fish will enjoy eating it, but if left on its own, will cause problems. It tends to grow in clumps that can easily be scraped off although it can return quickly.
Beard Algae — Similar to Hair Algae but with very fine textured strands. This type of algae is difficult to remove manually.
Regular water changes — Not only will regular water changes reduce nutrients needed by algae, but they will ensure your fish have clean water, keeping them in top condition.
Reduce light — If algae is taking over your aquarium, try reducing the length and intensity of your light. Avoid direct sunlight.
Check your tap water — Make sure your tap water does not contain high levels of nitrates and phosphate. Both of these will contribute to algae growth.
Live plants — Although not a replacement for regular aquarium maintenance, plants consume the nutrients needed by algae, thereby reducing the amount of algae in your tank.
Reduce feeding — Excessive feeding will lead to high levels of nitrates which serve to feed algae.
Algae-eating fish — Several species of African cichlids will help control algae, such as Labeotropheus and Tropheus species. Another alternative is the introduction of Bristlenose plecos. In a few nights, a single pleco can remove most traces of algae from an aquarium.