What is Algae? Algae are simple, plant-like organisms that thrive in water when conditions are right. They are natural and even beneficial in small amounts, but excessive algae growth can make your tank look dirty and harm plant and fish health.
Common Types of Aquarium Algae:
1. Green Algae
• Green Spot Algae – Forms hard green spots on glass and plants.
• Green Water (Algae Bloom) – Causes cloudy, green water.
• Hair/Thread Algae – Long, stringy growth on plants and decorations.
2. Brown Algae (Diatoms)
• Common in new tanks with low light and excess silicates.
• Forms a dusty, brown film on glass, substrate, and decor.
3. Blue-Green Algae (Cyanobacteria)
• Technically a bacteria, not an algae.
• Spreads rapidly, forming slimy blue-green sheets.
• Often smells bad and is linked to excess organics and low water circulation.
4. Black Beard Algae (BBA)
• Dark, fuzzy growth on decorations and plant edges.
• Caused by unstable CO₂ levels and poor flow.
5. Staghorn Algae
• Looks like grayish-green hair or antlers.
• Common in low-maintenance tanks with nutrient imbalances.
What Causes this to happen?
1. Too Much Light
• Excessive Light Duration– If your lights are on for more than 8–10 hoursper day, algae can thrive.
• High-Intensity Light– Strong lighting without CO₂ and proper nutrient balance can trigger algae.
• Direct Sunlight– Sunlight hitting the tank can promote uncontrolled algae growth.
2. Excess Nutrients (Nitrates & Phosphates)
• Overfeeding– Uneaten food decays, increasing nitrates (NO₃⁻) and phosphates (PO₄³⁻), which feed algae.
• Fish Waste & Decaying Plants– High bio-load (too many fish or dead plant matter) releases excess nutrients.
• Tap Water with High Nitrates/Phosphates– Some tap water contains naturally high nitrate or phosphate levels.
3. Lack of Competition from Healthy Plants
• If fast-growing plants (like hornwort, anacharis, or floating plants) aren’t using up available nutrients, algae will.
• Poor plant health due to nutrient deficiencies can leave room for algae to take over.
4. CO₂ Imbalance (For Planted Tanks)
• If you’re using high light but no CO₂, plants struggle while algae thrive.
• Fluctuating CO₂ levels(e.g., turning CO₂ on and off inconsistently) can trigger algae blooms.
5. Poor Water Circulation
• Stagnant water allows nutrients to accumulate in certain areas, promoting algae growth.
• Ensure good water flow with a filter and, if needed, a small powerhead.
6. Irregular Water Changes
• Infrequent water changes allow nitrate and phosphate levelsto build up.
• Regular weekly 25–50% water changeshelp remove excess nutrients.
How to Get Rid of Green Algae
Reduce Light – Limit lighting to 6–8 hours per day and reduce intensity if necessary.
Control Nutrients – Avoid overfeeding, remove decaying matter, and test water for high nitrates/phosphates.
Increase Plant Growth – Fast-growing plants absorb excess nutrients, outcompeting algae.
Improve CO₂ Stability – If using CO₂, keep levels stable (20–30 ppm) and consistent.
Improve Water Flow – Make sure nutrients are evenly distributed throughout the tank.
Regular Maintenance – Clean algae manually, scrape glass, prune affected plants, and perform weekly water changes.
Use Algae-Eaters – Add otos, Siamese algae eaters, amano shrimp, or nerite snails to help keep algae in check.
How to Get Rid of Brown Algae (Diatoms)?
1. Physically Remove It
Wipe Down Surfaces – Use an algae scraper or sponge to clean the glass.
Vacuum the Substrate – Use a gravel vacuum to remove settled diatoms.
Scrub Decorations & Rocks – Take them out and rinse or scrub with a soft brush.
2. Improve Lighting
Increase Light Intensity – Brown algae thrive in low-light conditions. Boosting your light can encourage green plant growth instead.
Adjust Light Duration – Maintain a consistent 6–8 hour photoperiod to discourage excess algae.
3. Control Nutrients (Reduce Silicates & Phosphates)
Perform Regular Water Changes – Replace 25–50% of tank water weekly to remove excess nutrients.
Use RO/DI Water – If your tap water has high silicates, switch to RO/DI filtered water.
Reduce Overfeeding – Excess fish food can break down and fuel algae. Feed small amounts that fish can consume in 1–2 minutes.
Clean the Filter Regularly – Rinse filter media monthly to prevent organic buildup.
4. Add Algae-Eaters
Certain species eat brown algae and help keep it under control:
• Otocinclus Catfish – Small and peaceful, great for planted tanks.
• Amano Shrimp – Excellent at consuming diatoms.
• Nerite Snails – One of the best algae eaters for glass and decor.
5. Improve Water Flow & Oxygenation
Increase Water Circulation – Use a small powerhead or adjust filter output to reduce dead spots.
Add an Air Stone – More oxygen can help beneficial bacteria outcompete diatoms.
6. Be Patient (Especially in New Tanks)
• Brown algae are common in newly cycled aquariums (0–3 months old).
• As beneficial bacteria establish, diatoms often disappear on their own.
If your tank is older than 3 months and still has brown algae, check for high silicates, poor circulation, or excessive nutrients.
By following these steps, brown algae should disappear within a few weeks!
How to Get Rid of Blue-Green Algae (Cyanobacteria)
1. Physically Remove as Much as Possible
Manually Scrape & Siphon It – Use an algae scraper or sponge to wipe it off surfaces.
Vacuum the Substrate – Use a gravel vacuum to remove loose BGA from the substrate.
Remove Affected Decorations & Plants – Rinse them under water and scrub off the algae.
2. Reduce Excess Nutrients (Starve the Cyanobacteria)
Perform Large Water Changes – Do a 50% water change, then 25-50% weekly to lower nitrate and phosphate levels.
Reduce Overfeeding – Uneaten food breaks down and releases excess nutrients. Feed only what fish can eat in 1-2 minutes.
Improve Filtration – Clean or replace filter media regularly to prevent organic buildup.
Use Phosphate Removers – Products like Seachem PhosGuard help reduce phosphate levels in the water.
3. Improve Water Flow & Oxygenation
Increase Circulation – BGA thrives in low-flow, stagnant areas. Add a powerhead or adjust filter output to improve water movement.
Use an Air Stone – Extra oxygenation helps beneficial bacteria outcompete cyanobacteria.
4. Use Natural Algae-Eaters (Limited Effectiveness)
Some creatures may help keep BGA under control but won’t eliminate it:
• Amano Shrimp– Occasionally eat thin layers of BGA.
• Nerite Snails– Can graze on some patches but won’t stop an outbreak.
5. Blackout Treatment (Starve the BGA of Light)
Turn Off the Aquarium Lights for 3–4 days (cover the tank with a blanket if needed).
Perform a Large Water Change (50%) afterward to remove dead algae.
Increase Circulation & Nutrient Control to prevent regrowth.
6. Treat with Chemicals (If Severe Infestation)
If BGA is persistent, you can use:
Erythromycin (Maracyn) – A mild antibiotic that kills cyanobacteria without harming fish or beneficial bacteria.
Hydrogen Peroxide (H₂O₂) Spot Treatment – Use a 3% H₂O₂ solution with a syringe to directly treat affected areas. Turn off the filter for 10–15 minutes, then resume normal flow.
⚠️ Use antibiotics as a last resort, as they can disrupt the tank’s ecosystem.
7. Prevent Future Blue-Green Algae Outbreaks
Maintain Good Water Quality – Keep nitrates below 10 ppm and phosphates below 0.05 ppm.
Improve Water Circulation – Make sure there are no dead zones in the tank.
Regular Maintenance – Weekly water changes, filter cleaning, and substrate vacuuming prevent excess nutrients.
By following these steps, you can completely eliminate and prevent Blue-Green Algae from coming back in your tank!
How to Get Rid of Black Beard Algae (BBA)
1.Manually Remove as Much as Possible
Trim Affected Plants – If plants are heavily covered, trim the affected leaves to prevent regrowth.
Scrub Decorations & Hard Surfaces – Remove driftwood, rocks, and decorations and scrub them under running water.
Use a Toothbrush or Algae Scraper – Physically scrub off BBA from surfaces before further treatment.
2. Balance Light & CO₂ Levels (For Planted Tanks)
Increase & Stabilize CO₂ Injection – If you’re using CO₂, keep it at 20-30 ppm and ensure stable levels throughout the day.
Use Liquid Carbon (Seachem Excel or API CO₂ Booster) – Daily dosing can weaken and kill BBA over time.
Adjust Light Intensity & Duration – Reduce excessive lighting to 6-8 hours per day to prevent overgrowth.
3. Treat with Spot Dosing (H₂O₂ or Liquid Carbon)
Hydrogen Peroxide (H₂O₂) Spot Treatment:
• Use a 3% H₂O₂ solutionin a syringe and apply directly to affected areas.
• Turn off the filter for 10-15 minutesto let the peroxide work.
• After treatment, BBA will turn red or whiteand die within a few days.
Liquid Carbon (Seachem Excel) Spot Treatment:
• Turn off the filter and apply directly to the algaeusing a syringe.
• Works best when applied dailyfor 5-7 days.
4. Introduce BBA-Eating Fish & Invertebrates
While they won’t eliminate BBA alone, they help control regrowth:
• Siamese Algae Eaters (SAE)– The best BBA eater, but must be true Siamese algae eaters (Crossocheilus siamensis).
• Amano Shrimp– Can eat small patches of BBA.
• Florida Flagfish– Known to nibble on BBA in planted tanks.
• Nerite Snails– Help clean surfaces but don’t eat BBA directly.
5. Improve Water Flow & Reduce Organics
Increase Water Circulation – Stagnant areas encourage BBA growth. Add a small powerhead or adjust filter flow.
Clean Your Filter Regularly – Rinse mechanical media in tank water every 2-4 weeks to prevent organic buildup.
Perform Regular Water Changes – 25-50% weekly to remove excess nutrients that fuel algae.
Reduce Overfeeding – Uneaten food increases organic waste, feeding BBA.
6. Control Nutrients (Balance Phosphates & Nitrates)
Keep Phosphate Levels in Check – Maintain phosphates (PO₄³⁻) below 0.05 ppm. Use phosphate removers (like Seachem PhosGuard) if necessary.
Maintain Nitrate Levels – Keep nitrates (NO₃⁻) between 10-20 ppm to promote healthy plant growth.
Encourage Fast-Growing Plants – Plants like hornwort, anacharis, and floating plants help outcompete algae for nutrients.
7. Extreme Measures (Only If BBA Persists)
Blackout Treatment – Turning off all light and covering the tank for 3-4 days can kill stubborn algae.
Bleach Dip (For Hardscape Only) – If decorations are heavily covered, dip them in a 1:20 bleach solution (1 part bleach, 20 parts water) for 1-2 minutes, then rinse thoroughly.
Boil or Sun-Dry Rocks & Driftwood – This kills BBA spores before reintroducing them to the tank.
How to Prevent BBA from Returning
Maintain Stable CO₂ Levels – BBA thrives in fluctuating CO₂ conditions.
Keep Water Circulation Strong – No dead zones where detritus accumulates.
Limit Excess Organics – Regular maintenance and water changes help prevent nutrient buildup.
Monitor Light & Nutrients – Balance plant growth and avoid excessive lighting.
By following these steps, Black Beard Algae will weaken, die off, and not return!
How to get rid of Staghorn Algae
1. Manually Remove as Much as Possible
Scrub Affected Surfaces – Use a toothbrush or algae scraper to remove algae from hard surfaces.
Trim Affected Plant Leaves – If plants have heavy infestations, prune the affected areas.
Vacuum the Substrate – Use a gravel vacuum to remove loose algae and decaying organic matter.
2. Improve CO₂ Levels & Stability
Increase & Maintain CO₂ Levels (Planted Tanks) – Staghorn algae thrive in low or fluctuating CO₂. Ensure CO₂ is 20-30 ppm and consistent.
Use Liquid Carbon (Seachem Excel or API CO₂ Booster) –
• Spot dose liquid carbon directly on the algae with a syringe.
• Daily dosing weakens the algae, causing it to turn red and die within 5-7 days.
3. Balance Lighting & Reduce Excess Nutrients
Reduce Light Duration – Keep lighting at 6-8 hours per day to prevent excessive algae growth.
Perform Regular Water Changes – 25-50% weekly to remove excess organic waste and nutrients.
Limit Overfeeding – Excess fish food increases nitrate (NO₃⁻) and phosphate (PO₄³⁻), fueling algae growth.
Use Phosphate Removers – If phosphates are too high, use Seachem PhosGuard or a similar product.
4. Improve Water Flow & Filtration
Increase Water Circulation – Staghorn algae thrive in stagnant areas. Add a small powerhead or adjust filter flow.
Clean Filter Media Regularly – Rinse sponge and mechanical media every 2-4 weeks in aquarium water (not tap water) to prevent organic buildup.
5. Introduce Algae-Eating Fish & Invertebrates
Some species eat small amounts of Staghorn algae, but manual removal and water quality improvements are needed for full control:
• Siamese Algae Eaters (SAE)– One of the best natural removers.
• Amano Shrimp– Occasionally nibble on weakened Staghorn algae.
• Nerite Snails & Otocinclus– Help with general algae control but not highly effective on Staghorn algae.
6. Hydrogen Peroxide (H₂O₂) Spot Treatment (If Necessary)
Use a 3% H₂O₂ solution with a syringe and apply directly to affected areas.
Turn off filters and water movement for 10-15 minutes, then resume normal flow.
Dead algae will turn red, then dissolve within a few days.
7. Prevent Future Staghorn Algae Growth
Maintain stable CO₂ levels (avoid fluctuations).
Keep water circulation strong (no dead zones).
Perform regular maintenance (water changes, filter cleaning, substrate vacuuming).
Balance light & nutrients to promote healthy plant growth.
By following these steps, Staghorn algae will weaken, die off, and not return!