Brown algae, often known as diatoms, commonly appear in aquariums primarily due to excess ammonia present in the water. This issue is particularly prevalent in newer aquarium setups where the essential populations of beneficial bacteria, crucial for processing waste like ammonia, have not yet fully developed.
Understanding Brown Algae (Diatoms)
While often called "brown algae," these organisms are actually diatoms, a type of single-celled organism with intricate silica cell walls. They thrive in specific water conditions and can quickly form unsightly brown patches on various surfaces within the aquarium.
Where Do They Appear?
- Aquarium glass
- Plant leaves
- Hardscape (rocks, driftwood)
- Substrate
The Main Cause: Excess Ammonia
Based on established aquarium practices and the provided reference, the primary driver for brown algae growth, especially in new tanks, is an abundance of ammonia.
Here's a breakdown of why this happens:
- New Tank Syndrome: When an aquarium is first set up, there isn't enough beneficial bacteria living in the filter media and substrate. These bacteria are vital for the nitrogen cycle, a natural process that converts harmful ammonia (produced by fish waste, uneaten food, decaying plant matter) into less toxic substances.
- Lack of Bacterial Population: Until the beneficial bacteria colony is large enough, ammonia levels can spike.
- Diatom Food Source: Diatoms utilize silicates and excess nutrients, including ammonia and other nitrogenous compounds that accumulate when the nitrogen cycle isn't functioning correctly.
Reference Insight:
The reference specifically states: "The cause is mainly down to excess ammonia, often found in new set-ups where the tank is yet to mature and have enough population of beneficial bacteria."
This directly links the appearance of brown algae to the immature state of the aquarium's bacterial ecosystem and the resulting high ammonia levels.
Factors Contributing to Brown Algae
While excess ammonia is the main trigger in new tanks, other factors can contribute or sustain diatom growth:
- Silicates in Water: Diatoms use silicates to build their cell walls. Tap water can sometimes contain silicates, providing this necessary building block.
- Excess Nutrients: Beyond ammonia, high levels of nitrates and phosphates (which can also be present in source water or accumulate from waste) can fuel algae growth.
- Lighting: While diatoms don't require intense light like some green algae, standard aquarium lighting is sufficient for their growth when nutrients are abundant.
Managing Brown Algae
The most effective way to combat brown algae, particularly in new tanks, is to address the root cause: the immaturity of the nitrogen cycle and resulting excess ammonia.
Here's a simple approach:
- Let the Tank Mature: Be patient during the initial cycling phase of a new aquarium. This period allows beneficial bacteria to establish. Avoid overstocking with fish too soon.
- Manage Ammonia:
- Perform regular partial water changes to dilute ammonia.
- Avoid overfeeding fish.
- Remove uneaten food promptly.
- Manual Removal: Physically wipe brown algae off surfaces during water changes.
- Introduce Algae Eaters: Certain aquarium inhabitants, like Otocinclus catfish or Nerite snails, are known to eat diatoms. Introduce them cautiously once the tank is stable.
- Address Silicates (Optional): In persistent cases, using an aquarium filter media designed to absorb silicates can help, though addressing the nutrient imbalance (ammonia/nitrogen cycle) is usually more effective.
Quick Overview: Brown Algae Causes & Solutions
| Cause | Context | Solution |
|---|---|---|
| Excess Ammonia | New, uncycled tank | Let tank mature, water changes, avoid overfeeding |
| Lack of Beneficial Bacteria | New tank | Allow bacteria to establish (cycling process) |
| Silicates | Source water | Silicate absorption media (less common solution) |
| Excess Nutrients (General) | Overfeeding, waste buildup | Water changes, nutrient control |
In summary, brown algae in an aquarium is a common, often temporary issue, especially in new setups. It signals an imbalance, primarily driven by excess ammonia due to an underdeveloped beneficial bacteria colony. Focusing on maturing the tank and managing nutrients is key to resolving it.
