Quick Answer
Blue-green algae is actually cyanobacteria. It can form slimy sheets with a strong smell and may spread quickly across substrate, glass, and plant leaves when flow and nutrient balance are poor.
Care and Setup Notes
- Remove mats physically before they break apart and spread.
- Increase water movement in stagnant areas.
- Check nitrate, phosphate, feeding, and dead organic pockets in the substrate.
What to watch
Use this page as a planning profile, then match the advice to your exact tank size, livestock, temperature, filtration, and water test results. If livestock are already stressed, test ammonia, nitrite, nitrate, pH, and temperature before making big changes.
Image: Wikimedia Commons fish photo used as contextual aquarium reference