There’s nothing more frustrating than watching your beautifully aquascaped tank slowly disappear behind a cloudy green film. Algae buildup on aquarium glass is one of the most common problems fishkeepers face — but with the right approach, it’s entirely manageable.

In this article, we’ll explain why algae grows on your aquarium glass, how to clean it effectively, and tips to prevent it from coming back. Whether you’re a first-time aquarist or a seasoned hobbyist, here’s how to keep your tank glass sparkling clean.

Why Does Algae Grow on Aquarium Glass?

Algae is a natural part of any aquatic environment, but excess growth on your tank walls is usually a sign that something’s out of balance. Common causes include:

• Too much light (especially direct sunlight or extended lighting periods)

• Excess nutrients (like nitrates and phosphates from overfeeding or waste buildup)

• Infrequent water changes

• Lack of proper tank maintenance

How to Remove Algae from Aquarium Glass

Here’s how we recommend clearing your fish tank glass of algae safely and effectively:

1. Use the Right Tools

Invest in an algae scraper or magnetic glass cleaner. These tools let you clean the glass without disturbing your fish or plants.

• For glass tanks: Use a standard algae scraper or magnetic cleaner with a blade attachment.

• For acrylic tanks: Use a soft sponge or acrylic-safe scraper to avoid scratches.

2. Don’t Use Household Cleaners

Never use window sprays, bleach, or chemical cleaners. These are toxic to fish and can linger in the water. Stick to aquarium-safe tools and techniques only.

3. Manual Removal During Water Changes

During routine maintenance, scrape down the glass before you siphon water. This allows any loosened algae to be removed with your gravel vacuum or siphon hose.

4. Target Stubborn Spots

For green spot algae (tough, circular patches), a razor blade or specialist algae pad works well on glass — but always be cautious near seals and corners.

How to Prevent Algae Build-Up on Glass

Once you’ve got the tank looking good, here are our top tips to keep it that way:

✅ Control Your Lighting

• Limit aquarium lights to 8–10 hours per day.

• Avoid placing tanks near windows or in direct sunlight.

✅ Feed Sparingly

• Overfeeding leads to uneaten food and nutrient spikes — perfect fuel for algae.

• Feed only what your fish can consume in 2–3 minutes.

✅ Regular Water Changes

• Perform weekly or biweekly water changes to remove excess nutrients.

• Clean filters regularly to avoid buildup of organic waste.

✅ Add Algae Eaters

• Species like Siamese algae eaters, otocinclus, nerite snails, or plecos can help control growth — but make sure they’re compatible with your tank setup.

✅ Maintain a Balanced Tank

• A healthy, stable environment is the best defence. Proper filtration, water testing, and plant management all play a part in algae control.

When to Call in the Pros

If your tank suffers from persistent algae blooms despite regular care, it might be time to bring in an expert. At South Devon Pond Maintenance, we offer professional fish tank cleaning and maintenance services across South Devon — ensuring your aquarium stays clean, healthy, and algae-free.