Nature's Cleanup Crew: How to Combat Aquarium Algae Without Chemicals
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Algae is one of the most common frustrations in the planted aquarium hobby — and one of the most misunderstood. Before reaching for a bottle of algaecide, it's worth understanding why algae grows in the first place, and how nature has already provided the perfect solution.
At Chloe's Aquatic Centre, we don't use harsh chemicals to keep our display tanks and plant systems spotless. Instead, we rely on a carefully selected team of natural algae grazers — the same animals we stock for your tank.
Why Does Algae Grow?
Algae thrives when there is an imbalance in your aquarium's ecosystem. The most common causes include:
- Excess light — Too many hours of light, or light that is too intense, fuels algae growth. Most planted tanks do best with 6–8 hours of quality light per day.
- Nutrient imbalance — Elevated nitrates, phosphates, or ammonia (often from overfeeding or insufficient filtration) give algae the food it needs to explode.
- Low CO₂ or poor plant competition — Healthy, fast-growing plants outcompete algae for nutrients. When plants are struggling — often due to insufficient CO₂ or fertiliser — algae fills the gap.
- Inconsistent maintenance — Irregular water changes, dirty substrate, and neglected filter media all contribute to the conditions algae loves.
Prevention First
The best algae strategy is a stable, balanced tank:
- Use a timer for consistent lighting — 6 to 8 hours per day is ideal for most planted setups.
- Dose CO₂ and fertilisers consistently to keep plants thriving and competitive.
- Perform regular water changes (30–50% weekly) to dilute excess nutrients.
- Don't overfeed — uneaten food breaks down into nitrates and phosphates rapidly.
- Stock your tank with a natural cleanup crew from day one.
Meet the Cleanup Crew
Siamese Algae Eater (Crossocheilus oblongus) — Hair Algae & Black Beard Algae
The Siamese Algae Eater (SAE) is one of the most effective algae-control fish available to the hobbyist. They are particularly renowned for tackling hair algae (also called thread algae or string algae), which forms long, wispy green strands that can quickly smother plants and hardscape.
SAEs are also one of the very few fish that will consume Black Beard Algae (BBA) — a stubborn, dark brush-like algae that clings to plant leaves, driftwood, and equipment. Importantly, younger SAEs are far more enthusiastic BBA grazers than adults, so introducing them early — before BBA becomes established — yields the best results. As they mature, their appetite for algae can diminish, so pairing them with other grazers is recommended for long-term control.
Why BBA grows: Black Beard Algae is typically triggered by fluctuating or insufficient CO₂ levels. Stabilising your CO₂ injection and ensuring consistent diffusion is the most effective prevention strategy.
Why hair algae grows: Hair algae is commonly associated with excess light and elevated phosphates. Reducing photoperiod and performing regular water changes will help keep it in check alongside your SAEs.
Otocinclus Catfish (Otocinclus spp.) — Soft Green Algae & Diatoms
The humble Otocinclus — affectionately known as "Otos" — is a small, peaceful catfish that is extraordinarily effective at grazing soft green algae and diatoms (brown algae) from plant leaves, glass, and hardscape.
Diatoms are extremely common in new aquarium setups, appearing as a brown, dusty film across surfaces. They are caused by elevated silicates and unstable water chemistry in newly cycled tanks, and typically resolve on their own as the tank matures — but Otos dramatically accelerate this process.
Soft green algae on plant leaves is one of the most damaging forms for a planted tank, as it blocks light and smothers delicate foliage. Otocinclus are gentle enough to graze directly on even the most fragile plant leaves without causing damage — making them an essential addition to any planted aquarium.
Why soft algae and diatoms grow: New tank syndrome, high silicates in tap water, and inconsistent lighting are the primary culprits. Otos, combined with a stable light schedule and regular water changes, will keep these under control.
Nerite Snail (Neritina spp.) — Green Spot Algae
Green Spot Algae (GSA) appears as small, hard, circular green dots on aquarium glass and slow-growing plant leaves. It is one of the most stubborn algae types to remove manually — but Nerite Snails are uniquely equipped to handle it.
Nerites have a radula (a rasping tongue-like organ) strong enough to scrape GSA directly off glass and plant surfaces, leaving them spotless. They are tireless workers, grazing constantly throughout the day and night, and they will not harm your plants or disturb your substrate.
An added bonus: Nerite Snails cannot reproduce in freshwater (they require brackish water to breed), so you'll never face a snail population explosion in your tank.
Why GSA grows: Green Spot Algae is most commonly linked to low phosphate levels or insufficient CO₂. If GSA is persistent, consider slightly increasing your phosphate dosing and checking your CO₂ distribution.
How We Use Them at Chloe's Aquatic Centre
Every display tank and plant holding system at Chloe's Aquatic Centre is maintained using these natural grazers — no algaecides, no harsh treatments. Our Siamese Algae Eaters patrol for hair algae and BBA, our Otocinclus keep plant leaves and glass crystal clear, and our Nerite Snails ensure the glass stays free of green spot algae.
The result? Lush, spotless plants that are healthy, vibrant, and ready for your aquarium. When you purchase plants from us, you're receiving stock that has been grown and maintained in a clean, chemical-free environment — the same standard we encourage you to maintain at home.
If you'd like to build your own natural cleanup crew, browse our range of Siamese Algae Eaters, Otocinclus, and Nerite Snails — all available in store and online.
Have questions about algae control or building the right cleanup crew for your setup? Reach out to our team — we're always happy to help.