How to Get Rid of Algae in Your Aquarium (and Keep It Away)

By Melbourne Tropical Team ยท 2 min read

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Algae is the most common aquarium frustration. Here is what causes it, how to remove each type, and the simple routine that keeps it from coming back.

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Why algae grows

Algae is fuelled by an imbalance of light and nutrients. Too much light (or direct sunlight), too long a lighting period, excess nutrients from overfeeding or poor maintenance, and not enough live plants to compete - any of these tips the balance in algae's favour. Fix the balance and algae fades on its own.

The main types and how to beat them

Green spot algae on glass and slow leaves - scrape the glass and increase phosphate slightly; it often signals low nutrients. Green dust/film - wipe it off and let the tank mature. Hair/thread algae - remove by hand (twirl it onto a toothbrush), reduce light and nutrients, and add fast plants. Black beard algae (BBA) - the toughest; spot-treat with liquid carbon, improve CO2 and flow, and remove affected leaves. Brown algae (diatoms) - normal in new tanks, it usually vanishes as the tank matures, and otocinclus and nerite snails eat it.

Your algae clean-up crew

Some animals genuinely help. Nerite snails are the best algae-eating snails and can't breed in freshwater; Amano shrimp and cherry shrimp graze hair and soft algae; bristlenose plecos and otocinclus eat green and brown films. They are helpers, not a cure - you still need to fix the underlying balance. Browse our plant guides and fish database for the best options.

The routine that prevents algae

Run lights 6-8 hours a day on a timer, keep the tank out of sunlight, feed sparingly, do regular water changes, grow plenty of live plants (especially fast and floating ones), and don't overstock. Get those right and algae becomes a minor, occasional chore rather than a constant battle.

Frequently Asked Questions

What eats algae in a fish tank?
Nerite snails, Amano and cherry shrimp, otocinclus catfish and bristlenose plecos all eat algae. They help, but you must also fix the light/nutrient balance.
Why do I keep getting algae?
Almost always too much light (or sunlight), too long a light period, overfeeding, or too few live plants. Reduce light to 6-8 hours, feed less, and add fast-growing plants.
How do I get rid of black beard algae?
Spot-treat it with liquid carbon, boost CO2 and water flow, remove badly affected leaves, and keep nutrients stable. It is the most stubborn algae and needs persistence.
Is algae bad for my fish?
Most algae is harmless to fish and even grazed as food. It is mainly an eyesore and a sign your tank's balance is off, so treat it as a useful warning.
Melbourne Tropical Team
Australian aquarium hobbyists sharing practical, tested fishkeeping advice.

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