Cladophora (wiry green mesh): Identification & Treatment
A tough, dark green tangled mesh of coarse branching strands with a musty smell — stiffer and wirier than soft hair algae.
Cladophora (wiry green mesh)
Cladophora (wiry green mesh) is one of the algae types Studio Scaped tracks in freshwater and brackish aquariums. This guide covers how to tell it apart from the types it is most often confused with, what conditions bring it on, the readings worth taking before you treat, and how to stop it returning. In most tanks the deciding factor is CO₂ stability.
How to identify cladophora (wiry green mesh)
A tough, dark green tangled mesh of coarse branching strands with a musty smell — stiffer and wirier than soft hair algae.
Compare the photograph above with your own tank before treating: several algae types look alike at a glance but respond to completely different corrections, and treating the wrong one wastes weeks. If you are unsure, the full identification guide sets the common types side by side.
Why it appears
Algae is a symptom rather than the disease. In this case the usual trigger is often introduced on new plants or hardscape rather than appearing spontaneously. The full list of causes worth ruling out:
- Often introduced on new plants or hardscape rather than appearing spontaneously
- Establishes where flow is poor and organics collect
- Nutrient imbalance in a high-light planted tank
- Grows into moss and carpet plants where it is difficult to reach
What to measure, and what the readings mean
| What to measure | Typical target | What an off reading points to |
|---|---|---|
| Nitrate (NO₃⁻) | 5–20 ppm planted · under 10 ppm reef | Climbing nitrate signals more waste going in than water changes and plants export. Near zero in a planted tank starves plants and favours algae. |
| Phosphate (PO₄³⁻) | 0.5–1.5 ppm planted · under 0.1 ppm reef | Often blamed for algae, but stripping it to zero usually backfires: plants stall first and algae takes the space. |
| CO₂ | 20–30 ppm while lights are on (injected tanks) | Instability drives more algae than the absolute level. Check it is up to level before lights on and holding through the photoperiod, not just peaking mid-day. |
| Light intensity and photoperiod | 6–8 hours for most planted tanks | Light beyond what your plants can use is left over for algae. Reduce duration before intensity — it is the easier variable to control. |
| Filtration and flow | 4× tank volume per hour freshwater · 6×+ reef | Low turnover leaves dead spots where detritus settles. Check working flow rather than the box rating, which assumes clean media and no head height. |
| Plant mass and health | growing actively, not melting | Healthy plants outcompete algae for the same nutrients. Melting or stalled plants free those nutrients up. |
Take these readings before changing anything. Treating without a baseline leaves you unable to tell which correction worked, and algae problems usually have more than one contributing cause.
Treatment & fixes
- Manual removal is essential — it will not be grazed away and tolerates most treatments
- Remove badly infested moss or carpet sections rather than trying to pick it clean
- Quarantine and inspect new plants before adding them
- Improve flow and increase water changes to reduce organics
- Be persistent: fragments left behind regrow, so repeat removal over several weeks
Keeping it from returning
- Keep CO₂ steady through the whole photoperiod — instability drives this type harder than the absolute level
- Reduce photoperiod before intensity; light your plants cannot use is left over for algae
- Keep flow reaching the whole tank — dead spots are where this establishes first
- Dose to your plant mass, not to zero — starving the tank starves plants first
- Keep plants actively growing — healthy plants outcompete this for the same nutrients
- Quarantine new plants and hardscape, which is how most algae arrives in the first place
Once corrected, cladophora (wiry green mesh) usually takes two to four weeks to visibly recede — existing growth does not disappear when the cause does, so remove what you can manually and judge success by whether new growth appears.
Related guides
- Hair algae — often confused with this type
- Rhizoclonium — often confused with this type
- Every algae type, side by side — for identification
- CO₂ injection — stability is the usual culprit here
- Lighting and spectrum
Frequently asked questions
How long before cladophora (wiry green mesh) clears up?
Expect two to four weeks after the cause is corrected. Manual removal is essential — it will not be grazed away and tolerates most treatments Existing growth generally has to be removed by hand — correcting conditions stops it spreading rather than dissolving what is already there.
Will algae eaters deal with it for me?
Grazers help hold a corrected tank clean; they rarely fix an uncorrected one. Amano shrimp pick at it but rarely keep up. Cladophora is tough and usually needs manual removal at the root.
Should I strip nutrients to starve it out?
Usually backfires. Plants stall before algae does, and the nutrients they stop using become available to the algae instead. Balance light, CO₂ and dosing to your plant mass rather than cutting fertilisation to zero.
