Why Algae Overgrows in Aquariums

Algae is completely normal in a tank and shows signs of a healthy aquarium.

The problem occurs when algae overgrows in aquariums and turns water green. Glass becomes slimy and fish start to suffer because of the nutrient imbalance.

Australian fishkeepers experience this in both tropical and coldwater tanks, especially during the warmer months when algae grows faster.

Excess Light 

Keeping aquarium lights on too long, or having your tank near direct sunlight.

We find this is one of the most common causes of algae problems when talking with our customers.

High Nutrient Levels 

Leftover food, fish waste, and decaying plants all release nitrates and phosphates, fueling rapid algae growth.

One of the most effective ways to get rid of algae in your fish tank is to monitor and control the nutrient levels in the water.

Irregular Maintenance 

Without regular water changes, nutrients build up and algae flourishes.

Regular maintenance is essential for effective aquarium algae control.

Inefficient Filtration

Clogged or undersized filters struggle to clear waste, creating the perfect environment for algae.

Common Types of Aquarium Algae

Green Water Algae

Makes water look like pea soup.

Suspended algae (floats in the tank).

Can multiply extremely quickly often requiring a green water algae treatment (add a UV steriliser to your tank).

Hair Algae 

Looks like green fuzz or fine stringy strands or threads.

Often clings to plants, rocks or glass. Spreads quickly if not controlled.

The best algae remover to use is a chemical algaecide. Some good ones we like are API's Algaefix or Aqua One's Algae Eliminator.

Diatom (Brown Algae) 

Looks like a soft brown or rusty looking film on glass.

Can coat gravel, plants, decorations and tank walls.

Common when cycling a new tank.

Black Beard Algae (BBA)

Brush-like growths. Colour may vary from dark green, grey to black.

Tufts may grown on wood, plants or filters.

Can be difficult to remove once established often needing targeted algae treatments.

Seachem Flourish Excel can help with treating BBA.

Green Spot Algae (GSA)

Hard green spots on glass and decorations.

Stubborn and can be tough to scrape off without a proper algae scraper tool.

The Mag-Float magnet cleaner with scraper is a popular choice amongst our customers.

Find the Best Algae Removing Kit for your Tank

All About Algae Control Products

Algaecides

• The most popular algae removers are liquid chemical treatments. They target existing algae such as green water & hair algae.
• Helps maintain clear water by inhibiting algae growth.

Algae Pads

• Coarse pads are ideal for removing stubborn algae and build-up on glass.
• Fine pads are excellent for regular maintenance and removal of light algae without scratching.

Water Testing Strips

• Use water test strips (like API 5 in 1 Test Strips) to monitor water conditions. 
• Regular testing can help you catch problems early before algae takes over.

Algae Scrapers

• Physically remove algae from surfaces with a scraper.
• Long-handled scrapers make it easy to reach and clean the bottom, behind decorations and near the substrate of your aquarium - perfect for larger or tall tanks.

Gravel Vacuums

• Regular substrate cleaning with a gravel vacuum in your aquarium easily removes waste and leftover food. It helps keep unwelcome nutrients low, cutting down on algae growth.