Thalassia testudinum (Turtle Grass) Care Guide
Thalassia testudinum, turtle grass, is a Caribbean seagrass with ribbon-like leaves up to 30 cm that demands a deep mature sand bed and strong lighting.
Overview
Thalassia testudinum, commonly called turtle grass, is a marine seagrass in the family Hydrocharitaceae. It grows from a long, jointed rhizome buried about 5-10 cm in the substrate, sending up linear ribbon-like leaf blades up to 30 cm long and around 2 cm wide with rounded tips. Its flowers are greenish-white, sometimes tinged pink.
Taxonomy
- Family: Hydrocharitaceae
- Genus: Thalassia
- Scientific name: Thalassia testudinum
- Order: Alismatales
Habitat
Turtle grass inhabits shallow, sandy waters of the Caribbean Sea and Gulf of Mexico, extending north to Cape Canaveral, Florida. It grows from the low-tide mark down to about 30 m where water is clear, on muddy sand, coarse sand and clayey calcareous seabeds. The plant tolerates salinity from 25 to 38.5 parts per thousand and temperatures of 20-30 °C. It is grazed by turtles, parrotfish, surgeonfish and sea urchins and supports many epiphytes and juvenile fish.
Growth requirements
- Water type: marine (saltwater)
- Temperature: 23-28 °C (73-82 °F)
- pH: 8.1-8.4
- Salinity: 25-38.5 ppt
- Lighting: high
- Growth rate: slow
In aquaria turtle grass is an advanced subject: long-term success depends on a deep, mature sand bed (DSB), strong lighting, stable parameters and patience, since the species establishes slowly.
Placement
The KB record places it in the background, the tallest of the seagrasses here at up to about 30 cm. Its ribbon leaves form a grass-like backdrop over a sand bed.
Propagation
It reproduces asexually by rhizome extension and sexually by flowering from about April to July depending on location; female plants produce a single green flower and males three to five flowers, with seeds developing two to four weeks after fertilisation. In aquaria spread is mainly through the creeping rhizome.