TankBud

Carolina mosquito fern

Azolla caroliniana

Also known as Carolina mosquitofern, Carolina water fern, Eastern mosquito fern

FreshwaterFloatingFragmentationDivision

Carolina mosquito fern (Azolla caroliniana)
"Azolla caroliniana" by s-a-m is licensed under CC BY 2.0. To view a copy of this license, visit https://creativecommons.org/licenses/by/2.0/. · by

Care at a glance

Light
Medium light
CO2
No CO₂ needed
Temperature
64–86°F
18–30°C
Max height
0.8 in
2 cm
Growth rate
Fast
Placement
Floating
Type
Floating
pH
5.0–8.0
Spread
11.8 in (30 cm)
Nutrient uptake
Water column
Growth region
Submersed or emersed
Difficulty
Easy
Family
Salviniaceae
Origin
Southeastern Canada to the central and eastern USA, the Caribbean and northern South America to eastern Brazil

Overview

Carolina mosquito fern is an easy, fast-spreading plant that floats in a flat, compact mat. It suits tanks with a calm surface.

Did you know

Carolina mosquito fern often lives through winters with hard frost and long ice cover. It is also the Azolla species best adapted to surviving on mud.

Caring for Carolina mosquito fern

Set Carolina mosquito fern on a calm surface with the tops of the fronds dry. Keep filter outflow and air stones away from the mat, since fronds that stay wet on top tend to rot.

Give it medium light. Strong light can turn the fronds pink, orange or red. It feeds from the water column, so dose a liquid fertilizer regularly, and it needs no added CO2. It grows at 64 to 86°F (18 to 30°C).

It spreads fast, because pieces that break off keep growing and each plant buds off new ones. Scoop out the extra often to keep light reaching the plants below. Fish do not usually eat it.

Good to know

Carolina mosquito fern is a fern in the family Salviniaceae, with stems only 0.5 to 1 cm long. POWO, GBIF and WFO all accept Azolla caroliniana as a species separate from A. filiculoides. Flowgrow disagrees and files the plant the hobby sells under this name as A. cristata. The shop plant lies flat on the water, while A. filiculoides grows looser shoots with raised tips.

In the wild

Carolina mosquito fern is native from southeastern Canada through the central and eastern USA, and south through the Caribbean to northern and eastern Brazil. It floats on shallow ponds, ditches and sluggish streams in full sun or part shade. It has also been introduced to several European countries and to Taiwan, Thailand, Vietnam and Peninsular Malaysia.

Common questions

Does Carolina mosquito fern need to be planted in the substrate?

No. Carolina mosquito fern floats at the surface and takes its nutrients straight from the water.

Does Carolina mosquito fern need CO2?

No. Carolina mosquito fern grows well without added CO2.

How much light does Carolina mosquito fern need?

Carolina mosquito fern wants medium light. A light sold for planted tanks covers it.

How do you propagate Carolina mosquito fern?

Carolina mosquito fern propagates by fragmentation and division. Pieces that break off keep growing, so pulling a clump apart spreads it. Each plant buds off new ones, so a few soon cover the surface.

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