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Nitella flexilis Care Guide

Nitella flexilis, the smooth stonewort, is a soft, fine-branched charophyte green alga of the family Characeae that lacks the calcification of Chara.

Overview

Nitella flexilis, the smooth stonewort, is a charophyte green alga in the family Characeae. Unlike Chara, it lacks heavy calcium-carbonate encrustation and is soft and finely branched, forming feathery green tufts. It is a robust species that can reach about one metre in length, with branchlets in whorls that are once or twice divided. It is widely used as a model organism because of its large cell size and ease of laboratory cultivation.

Taxonomy

  • Division: Charophyta
  • Class: Charophyceae
  • Order: Charales
  • Family: Characeae
  • Genus: Nitella
  • Scientific name: Nitella flexilis
  • Common name: Smooth stonewort

Origin

The genus Nitella was established by C. Agardh in 1824 and contains some 90 species of charophyte green algae. N. flexilis has a near-global distribution, occurring on all continents except Australia.

Habitat

It inhabits freshwater environments such as canals and other still or slow-moving waters. As a stonewort it grows submerged and anchors to the bottom, but unlike Chara it does not become calcified or stony.

Tank requirements

  • Temperature: 12-24 °C (coldwater)
  • pH: 6.0-8.0
  • GH: 4-18 °dGH
  • Lighting: medium
  • CO2: not required
  • Substrate: any (anchors by rhizoids)
  • Maximum height: about 25 cm in aquaria
  • Placement: background

Planting & care

The soft tufts anchor to the substrate and provide fine cover. The alga has a low nutrient demand and does not require CO2, and its delicate branchlets make it useful in coldwater and shrimp tanks where it offers shelter for young invertebrates.

Propagation

Propagation in cultivation is by division of established tufts.

Difficulty

The species is rated beginner-friendly. It is undemanding for light, nutrients and CO2, and tolerates a wide range of cooler water conditions.

Conservation status

IUCN Red List: Least Concern (3.1).

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