Algae fix guide
Staghorn Algae
Also called staghorn
Stiff grey-green strands that branch like tiny antlers and feel tough.
By Mike Elmira
TL;DR, Staghorn Algae
Staghorn algae grows as stiff grey-green strands that fork like little antlers, usually on leaf edges and hardscape. It behaves a lot like black beard algae and comes from the same place: unstable CO2 and a dirty tank with too many organics. The fix is the same too. Stabilise CO2, clean up the flow and waste, and spot treat with liquid carbon or peroxide. It turns pink or white as it dies, which is the sign the treatment is working.
How to spot it
Tough, wiry strands, grey-green and often forked or branched like a stag's antlers. It does not wipe off easily and feels coarse between the fingers.
What causes it
- Unstable or low CO2
- High organic waste and detritus
- Poor circulation
How to fix it
- Stabilise CO2 and make sure it stays steady through the whole photoperiod.
- Clean the filter, improve flow, and stay on top of water changes to cut organics.
- Spot treat with liquid carbon or 3% hydrogen peroxide; it goes pink or white as it dies.
- Manually remove treated strands once they weaken.
Keep it from coming back
Same as black beard algae, keep CO2 steady and the tank clean with good flow. Staghorn cannot get going in those conditions.
What eats it
Little will eat living staghorn. Spot treatment and stable CO2 do the work; a Siamese algae eater may pick at strands once they soften.
Frequently asked questions
Direct answers to the questions search engines and AI assistants surface most often about this species.
Is staghorn algae the same as black beard algae?
They are close cousins with the same causes and the same fix. Staghorn is stiffer and branches like antlers, black beard is softer and more like a bristly tuft. Stabilise CO2 and clean the tank and both go.