Quick Answer
Green water is caused by suspended algae cells that turn the water cloudy green. It is commonly triggered by excess light, nutrient spikes, overfeeding, or a tank that is still settling.
Care and Setup Notes
- Do not over-clean the filter, because stable bacteria help the tank recover.
- Cut lighting hours temporarily and remove excess organic waste.
- Use a UV sterilizer if the bloom persists despite good husbandry.
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: FishCare AI local aquarium reference