Underwater Eco Systems - Algae Control

"Diatom" Algae

Occurs in fresh and saltwater. This type of algae is usually the first to appear in a new tank. It requires silicates to grow. Relatively easy to scrape off glass and rocks, this type of algae is usually of no interest to algae-eating fish.

First, scrape off all that you can. Make sure your lighting schedule is appropriate, though this type of algae doesn't need much light to grow. Second, put some silicate-removing filtration media in your filter and monitor your silicate levels. Once those levels are under control, you should be rid of the algae. In saltwater, Astrea and Trochus snails take care of diatom algae relatively well.

Green Algae

Occurs in fresh and saltwater. The most common form of algae in aquaria, green algae is actually an indicator of good water conditions! Most algae eating fish will eagerly consume this type of algae, except for the green spot algae that appears on the aquarium glass. Another form of green algae is hair algae: long, coarse strands of 'hair'-like algae that can grow and spread very quickly. While easy to remove by hand, it can grow back rapidly!

Control green algae by controlling your lighting and nitrate levels. Soak up extra nitrates with a variety of nitrate-removing filtration media. Saltwater hair algae is a bit tougher to remove than freshwater, so you may need to scrub it. As for the algae on your glass, the most effective way to remove it is with a razor blade or coarse scrub pad. (show scrub pads, pro-scraper, nitrate media, etc)

Red/Black Brush or
Beard Algae

Occurs predominantly in freshwater. Tanks with higher pH or hardness tend to have the most trouble with this algae. The tiny, almost moss-like clumps are very hard to remove manually, and the only fish that will touch this algae is the true Siamese Algae Eater. The primary cause other than excess light is phosphates and silicates.

To remove this algae from ornaments/rocks, you can attempt to scrape or scrub it off, but the easiest way is to soak the item in bleach water. If it happens to grow on plant leaves (most likely Anubias) it's virtually impossible to remove, so just tear off the entire affected leaf. One last possible remedy is to treat the tank with copper medication, though use this only as a very last resort.

Slime/Blue-Green
Algae/Cyanobacteria

Occurs in fresh and saltwater. As the latter name implies this "algae" is actually a bacteria growth! This usually appears as a slimy growth in a variety of colors, most often a dark red or purple. It often smothers plants and grows very quickly. It can also release toxins that may be harmful to fish!

This algae is easy to remove by hand, but grows back rapidly. Increased water circulation can sometimes keep it from growing. Nitrate levels don't influence its growth, but slime algae may be affected by higher phosphate levels, so a phosphate-removing filtration media may help. Frequent water changes are helpful, as well. The anti-bacterial erythromycin will kill cyanobacteria, but this medication can also affect biological filtration bacteria, so be sure to check your ammonia/nitrite levels after using this medicine