What's eating my azolla pinnata?

Azolla pinnata is a floating aquatic fern kept in ponds and indoor water features. Its main threats are aphids and water snails that rasp or colonize fronds, plus pond fish that graze it heavily. Mosquito larvae can breed beneath dense mats but do not damage the plant itself. Keep colonies thinned to deter pests.

Clusters of small insects on frond surfaces cause yellowing and distorted growth; sticky honeydew promotes sooty mould. Dislodge with a strong water jet or introduce natural predators such as ladybirds. Remove heavily infested sections by hand.

Rasping feeding creates ragged holes in fronds and can reduce mats dramatically overnight. Hand-pick snails at dusk or use a snail trap. Avoid copper-based remedies near fish. Remove egg masses on container walls.

Fish graze fronds aggressively, stripping the mat down to bare water within days. Protect with fine mesh netting over the pond surface, or grow Azolla in a separate container away from fish.