Bring your aquatic dreams to life Search Cart (0)
Bring your aquatic dreams to life
The Algae Growing In Your Aquarium
Green film, fuzzy patches, tangled threads, brown dust, or cloudy green water often point to different aquarium imbalances. Match the algae below to understand what may be causing it and what usually helps reduce it.

Identify The Algae

Use the visual guide below to match common algae growth patterns found in aquariums before exploring the summary table and detailed algae cards further down the page.

Identify The Algae
1 2 3 4 5 6 7 8 9 10

Understanding The Full System

01

Green Dust Algae

Green glass film

Learn more →
02

Hair Algae

long green threads

Learn more →
03

Black Beard Algae

Black fuzzy edges

Learn more →
04

Blue-Green Algae

Slimy coat

Learn more →
05

Brown Diatoms

Brown dusty patches

Learn more →
06

Green Spot Algae

Dark green spots

Learn more →
07

Staghorn Algae

Grey branching strands

Learn more →
08

Blanket Weed

Thick tangled algae

Learn more →
09

Green Water

Light green water

Learn more →
10

Fuzz Algae

Soft fuzzy coating

Learn more →

Quick Summary

Scroll down for a fast overview of common algae causes and corrective actions.

Find Out More

Detailed Algae Causes & Solutions

Open the sections below to understand what commonly causes each algae type and what usually helps reduce or remove it.

Read Details

Keeping Algae Under Control

Read the overview at the bottom for simple maintenance habits that help reduce recurring algae problems over time.

Read Conclusion

Quick Algae Summary

Use this quick reference table to match the algae identified in the hotspot map above with their common causes and first corrective direction before opening the detailed algae cards below.

Algae Type Usual Cause What Usually Happened Corrective Action
Green Dust Algae Light, Nutrients High light intensity and excess nutrients coating glass surfaces. Reduce lighting and control fertiliser dosing.
Hair Algae Nutrients, Waste Excess nutrients with weak plant growth causing long green threads. Remove algae manually and reduce excess waste.
Black Brush Algae (BBA) Flow, Organics Poor circulation and trapped organics causing dark fuzzy patches. Improve flow and clean trapped debris.
Blue-Green Algae Waste, Dead Spots Organic buildup and low circulation creating slimy sheets. Increase circulation and vacuum sludge.
Brown Diatoms New Tank, Silicates Immature filtration causing dusty brown coating. Maintain regular cleaning and allow tank to mature.
Green Spot Algae Phosphate, Light Low phosphate causing hard green spots on glass and leaves. Scrape surfaces and improve nutrient balance.
Staghorn Algae Flow, Waste Dirty conditions and unstable circulation causing branching growth. Improve maintenance and circulation.
Blanket Weed Light, Nutrients Excess lighting and nutrients causing thick algae mats. Reduce lighting and remove dense growth.
Green Water Light, Nutrients Free-floating algae bloom turning water cloudy green. Reduce lighting and use UV steriliser if needed.
Fuzz Algae Nutrients, Weak Plants Excess nutrients coating slow-growing plants and surfaces. Improve plant growth and reduce excess feeding.
Algae Causes & Corrective Actions
Match common algae growth patterns, understand what usually causes them, and review practical corrective directions and support options.
Green dust algae coating aquarium glass
Glass Film Common

Green Dust Algae

Soft green film coating aquarium glass surfaces.

Light Nutrients Glass Surface Easy To Wipe
Tap To View Causes & Fixes ↓
Cause & Correction
Usually Linked To What Usually Happened Corrective Direction
Light Glass receives too much light for too long. Reduce lighting duration or intensity.
Nutrients Fertiliser or waste leaves excess nutrients in the water. Reduce dosing and remove trapped waste.
New Tank Tank biology has not settled yet. Clean glass weekly and avoid constant changes.
Extra Support Options

Natural Support

Nerite Snails Otocinclus Amano Shrimp

Product / Equipment Support

Magnetic Cleaner Algae Scraper UV Steriliser
Important Notes
  • Remove thick film manually before it builds up.
  • If it returns quickly, check lighting duration first.
  • Do not keep increasing fertiliser while glass algae is spreading.
Hair algae growing inside planted aquarium
Stringy Growth Common

Hair Algae

Long green stringy threads growing on plants, hardscape, and equipment.

Light Nutrients Waste Fast Spreading
Tap To View Causes & Fixes ↓
Cause & Correction
Usually Linked To What Usually Happened Corrective Direction
Light Lighting is too strong or left on too long. Reduce lighting duration or intensity.
Nutrients Excess nutrients build up faster than plants can use them. Reduce fertiliser dosing and improve maintenance.
Waste Trapped organics and decaying debris feed algae growth. Vacuum debris and improve water changes.
Weak Plants Slow or unhealthy plant growth leaves nutrients unused. Improve plant health and trim damaged leaves.
Extra Support Options

Natural Support

Amano Shrimp Siamese Algae Eater Mollies

Product / Equipment Support

Algae Twister Tool Aquarium Scissors Surface Skimmer
Important Notes
  • Manual removal helps prevent rapid spreading.
  • Long strands can smother mosses and carpeting plants.
  • Do not suddenly blackout planted tanks without understanding plant impact.
Black Brush Algae growing on aquarium plants and hardscape
Dark Fuzzy Growth Stubborn

Black Brush Algae (BBA)

Dark fuzzy tufts growing along plant edges, wood, rocks, and equipment.

Flow Organic Waste Hardscape Slow Growing
Tap To View Causes & Fixes ↓
Cause & Correction
Usually Linked To What Usually Happened Corrective Direction
Flow BBA develops around strong or unstable flow areas. Reduce dead spots and stabilise circulation.
Organic Waste Trapped waste and dirty filters feed algae growth. Improve cleaning and maintenance routines.
Unstable CO2 Plants struggle while algae adapts more easily. Keep CO2 and lighting more consistent.
Old Growth Slow-growing leaves collect algae over time. Trim badly affected leaves manually.
Extra Support Options

Natural Support

Amano Shrimp Siamese Algae Eater Florida Flagfish

Product / Equipment Support

Liquid CO2 Spot Treatment Syringe Aquarium Scissors
Important Notes
  • BBA usually does not disappear quickly even after conditions improve.
  • Dead BBA often turns reddish or grey before breaking apart.
  • Heavy spot treatment may affect sensitive plants, shrimp, or mosses.
Blue-green algae coating aquarium rocks and substrate
Slimy Sheet Fast Spreading

Blue-Green Algae

Slimy blue-green sheet coating rocks, substrate, plants, or glass.

Dead Spots Organic Waste Low Flow Can Smell Bad
Tap To View Causes & Fixes ↓
Cause & Correction
Usually Linked To What Usually Happened Corrective Direction
Dead Spots Low circulation lets slime grow across quiet areas. Redirect flow and improve movement near affected zones.
Organic Waste Trapped debris, dirty substrate, or old waste feeds the outbreak. Vacuum sludge and remove decaying material.
Poor Maintenance Waste builds up faster than the tank can process. Increase water changes and clean filter pre-media.
Low Nitrate Plants slow down while cyanobacteria spreads across surfaces. Check plant nutrition and avoid starving planted tanks.
Extra Support Options

Natural Support

Manual Removal Healthy Plant Growth Better Flow

Product / Equipment Support

Gravel Cleaner Powerhead Sludge Remover Cyanobacteria Treatment
Important Notes
  • This is usually cyanobacteria, not true algae.
  • Remove as much slime as possible before treatment.
  • Do not leave decaying sheets inside the tank after it dies.
Brown diatoms coating aquarium surfaces
Brown Dust Common In New Tanks

Brown Diatoms

Dusty brown coating appearing on glass, substrate, plants, wood, and rocks.

New Tank Silicates Low Light Easy To Wipe
Tap To View Causes & Fixes ↓
Cause & Correction
Usually Linked To What Usually Happened Corrective Direction
New Tank Tank biology and surfaces are still maturing. Continue regular maintenance and allow the tank to settle.
Silicates Silicates from water or substrate encourage brown dust growth. Increase water changes and improve filtration.
Low Light Plants grow slowly while brown coating spreads over surfaces. Improve lighting balance and plant growth.
Dirty Surfaces Dust collects over glass and hardscape over time. Wipe surfaces and vacuum loose buildup.
Extra Support Options

Natural Support

Otocinclus Nerite Snails Amano Shrimp

Product / Equipment Support

Magnetic Cleaner Gravel Cleaner Silicate Remover
Important Notes
  • Brown diatoms are very common during early tank setup stages.
  • Usually easier to control than BBA or hair algae.
  • Most brown dust wipes away easily during maintenance.
Green spot algae growing on aquarium plant leaves and glass
Hard Green Spots Slow Growing

Green Spot Algae

Hard dark green spots appearing on glass, Anubias leaves, and slow-growing plants.

Glass Slow Plants Lighting Hard To Scrape
Tap To View Causes & Fixes ↓
Cause & Correction
Usually Linked To What Usually Happened Corrective Direction
Strong Lighting Glass and slow-growing leaves receive long direct exposure. Reduce lighting duration or intensity.
Slow Plants Anubias and older leaves collect algae over time. Trim heavily affected leaves.
Imbalance Plants struggle while algae continues attaching to surfaces. Improve plant growth and maintenance consistency.
Old Glass Film Green spots harden and become difficult to remove. Scrape glass regularly before buildup thickens.
Extra Support Options

Natural Support

Nerite Snails Otocinclus Healthy Plant Growth

Product / Equipment Support

Glass Scraper Magnetic Cleaner Razor Blade Cleaner
Important Notes
  • Green spot algae usually becomes harder to remove if ignored for too long.
  • Older Anubias leaves are commonly affected first.
  • Thick spots often need manual scraping instead of wiping.
Staghorn algae growing inside planted aquarium
Grey Branching Growth Messy Spread

Staghorn Algae

Grey branching algae strands growing across plants, mosses, and carpeting areas.

Organic Waste Flow Dirty Areas Messy Appearance
Tap To View Causes & Fixes ↓
Cause & Correction
Usually Linked To What Usually Happened Corrective Direction
Organic Waste Waste and trapped debris collect around plants and substrate. Improve cleaning and remove decaying material.
Flow Issues Uneven circulation allows algae to spread through affected areas. Improve circulation and reduce stagnant zones.
Weak Plant Growth Plants struggle while algae spreads across leaves and moss. Improve plant health and trim damaged areas.
Old Build-Up Dirty mosses and carpeting plants trap algae strands over time. Manually remove affected growth regularly.
Extra Support Options

Natural Support

Amano Shrimp Siamese Algae Eater Healthy Plant Growth

Product / Equipment Support

Aquarium Scissors Spot Treatment Syringe Liquid CO2
Important Notes
  • Staghorn algae often traps itself inside mosses and carpeting plants.
  • Heavy infestations usually need manual trimming and removal.
  • Dead staghorn algae may turn reddish or pale before breaking apart.
Blanket weed growing heavily inside aquarium
Dense Tangled Growth Heavy Infestation

Blanket Weed

Thick tangled green algae mats covering plants, hardscape, and substrate areas.

High Light Nutrients Overgrowth Can Smother Plants
Tap To View Causes & Fixes ↓
Cause & Correction
Usually Linked To What Usually Happened Corrective Direction
High Lighting Strong lighting pushes algae growth faster than plants can keep up. Reduce lighting duration and intensity.
Excess Nutrients Fertiliser and waste build up inside the tank over time. Reduce excess dosing and improve maintenance.
Weak Plant Competition Slow or unhealthy plants leave nutrients unused. Improve plant health and trim damaged growth.
Neglected Build-Up Long algae strands spread and trap more debris over time. Remove large clumps manually before they spread further.
Extra Support Options

Natural Support

Amano Shrimp Siamese Algae Eater Mollies

Product / Equipment Support

Algae Twister Tool Aquarium Scissors Surface Skimmer
Important Notes
  • Blanket weed can quickly smother mosses and carpeting plants.
  • Large infestations usually need repeated manual removal.
  • Leaving thick algae mats inside the tank traps even more waste.
Green water algae bloom inside aquarium
Cloudy Green Water Floating Bloom

Green Water

Water turns cloudy green from suspended free-floating algae blooms.

Excess Light Nutrients Floating Algae Rapid Bloom
Tap To View Causes & Fixes ↓
Cause & Correction
Usually Linked To What Usually Happened Corrective Direction
Excess Lighting Strong lighting pushes rapid free-floating algae growth. Reduce lighting duration and intensity.
Nutrient Build-Up Waste and excess nutrients remain suspended in the water. Improve maintenance and reduce overfeeding.
Direct Sunlight Tank receives strong sunlight exposure during the day. Move the tank or block direct sunlight.
Weak Filtration Water quality declines while algae multiplies rapidly. Improve filtration and maintenance consistency.
Extra Support Options

Natural Support

Floating Plants Fast Growing Plants Reduced Feeding

Product / Equipment Support

UV Steriliser Fine Filter Floss Water Clarifier
Important Notes
  • Green water is usually caused by suspended algae, not dirty substrate.
  • UV sterilisers are one of the fastest ways to clear heavy blooms.
  • Large water changes alone may not solve recurring blooms if lighting remains excessive.
Fuzz algae growing on aquarium plants and grass
Soft Hairy Growth Fine Green Coating

Fuzz Algae

Short soft green algae coating plants, mosses, grass, and hardscape surfaces.

Light Organic Waste Soft Growth Can Spread Fast
Tap To View Causes & Fixes ↓
Cause & Correction
Usually Linked To What Usually Happened Corrective Direction
Excess Lighting Plants and surfaces receive too much light over time. Reduce lighting duration or intensity.
Organic Waste Trapped debris and excess waste feed algae growth. Improve cleaning and remove decaying material.
Weak Plant Growth Plants struggle while algae spreads over leaves and grass. Improve plant health and maintenance consistency.
Old Build-Up Soft algae slowly spreads across nearby surfaces. Trim affected areas and manually remove buildup.
Extra Support Options

Natural Support

Amano Shrimp Otocinclus Siamese Algae Eater

Product / Equipment Support

Aquarium Scissors Surface Skimmer Fine Filter Floss
Important Notes
  • Fuzz algae is softer and finer than hair algae or blanket weed.
  • Short trimming and manual removal usually help reduce spreading.
  • Healthy fast-growing plants often outcompete fuzz algae over time.
LONG-TERM ALGAE CONTROL

Keeping Algae Under Control

Most algae problems become easier to manage when lighting, nutrients, waste buildup, and maintenance routines stay more consistent over time.

Lighting & Nutrients

  • Avoid very long photoperiods
  • Reduce direct sunlight exposure
  • Avoid excessive fertiliser dosing
  • Feed only what fish can finish

Maintenance & Cleaning

  • Perform regular water changes
  • Vacuum trapped debris and sludge
  • Remove dead leaves early
  • Clean dirty glass before buildup thickens

Flow & Filtration

  • Reduce stagnant dead spots
  • Improve circulation around hardscape
  • Clean clogged filter media regularly
  • Prevent trapped organic buildup

Natural Algae Support

  • Nerite snails for glass algae
  • Amano shrimp for soft algae
  • Otocinclus for soft coatings
  • Siamese algae eaters for hair algae

Need help with another system? Return to the Care Hub for calculators, filtration guides, and ecosystem support.

Return to Care Hub ↗
`
 

My Wishlist

Loding your saved items

Don't lose your wishlist!

My Wishlist

Loding your saved items

Don't lose your wishlist!