Pest identification
What's eating my azolla filiculoides?
Algae
Signs: Filamentous or green-water algae entangle Azolla mats, block light, and out-compete for nutrients, causing frond yellowing.
Control: Partial water changes, reduce fertiliser, manual removal of algae; avoid still, warm, nutrient-rich water.
Fish (goldfish, koi, mosquitofish)
Signs: Fronds consumed rapidly; fish can clear an Azolla mat within days in an aquarium or small pond.
Control: Grow in a separate fish-free vessel or float a mesh frame to protect a seed colony; stock only small, non-herbivorous fish alongside it.
Aquatic snails
Signs: Fronds rasped and fragmented; in closed aquarium systems, snails can progressively thin the mat.
Control: Quarantine new plant material to prevent snail introduction; hand-remove snails; use assassin snails for biological control.
Keep azolla filiculoides pest-free
Healthy plants resist pests best. Get the basics right:
Azolla filiculoides pests — FAQ
What is eating my azolla filiculoides?
Azolla filiculoides (fairy water fern) grown indoors is mainly threatened by algae competition and by fish eating the fronds. Aquatic snails graze on colonies in closed systems. Water quality issues — especially high pH or sudden cold — bleach and crash colonies faster than insect pests. Keep water clean and nutrient-balanced to maintain healthy red-green colouration.
How do I get rid of algae on azolla filiculoides?
Filamentous or green-water algae entangle Azolla mats, block light, and out-compete for nutrients, causing frond yellowing. Partial water changes, reduce fertiliser, manual removal of algae; avoid still, warm, nutrient-rich water.
How do I get rid of fish (goldfish, koi, mosquitofish) on azolla filiculoides?
Fronds consumed rapidly; fish can clear an Azolla mat within days in an aquarium or small pond. Grow in a separate fish-free vessel or float a mesh frame to protect a seed colony; stock only small, non-herbivorous fish alongside it.
How do I get rid of aquatic snails on azolla filiculoides?
Fronds rasped and fragmented; in closed aquarium systems, snails can progressively thin the mat. Quarantine new plant material to prevent snail introduction; hand-remove snails; use assassin snails for biological control.