Category: Seagrass

Species of Thalassia are the most abundant marine plant in the Caribbean. A flat bladed, dark green sea grass featuring an extensive root system that securely anchors and protects the plants from tidal surge, storms and ocean currents. The leaves are ribbon-like, about ½ inch wide and often reach heights of up to 14 inches long. Turtle Grass, like most sea grasses, are very adaptable to survive in a wide range of salinities, ranging from 20 ppt. to 40 ppt. It can also survive exposure to air at low tide levels. Once the root system is disturbed or damaged it will not repair itself, which is why it can take a year or more for damaged beds to become restored. In the aquarium it requires a moderate depth of sediment (6-8″ minimum) for its deep rhizome network. The root system spreads by lateral growth of the rhizomes at their ends and is the most common form of reproduction. Sand beds that are rich in organic material are best, but plants can be fertilized by inorganic means such as dry and liquid plant food. 

Scientific Name: Thalassia testudinum

Common Name: Turtle Grass

Origin: Gulf of Mexico, Atlantic, Caribbean

Depth Collected: 4 -80 Feet

Maximum Height : 14″

Growth Rate: Slow

Light: High

Temperature: 78-86

Propagation: Rhizomes, Seeds

Difficulty: Advanced

Food Value: Palatable to some fish

Nutrient Uptake: Good once established

Flow Rate: Moderate to High

Shoal Grass features thin, flat bladed leaves that resemble terrestrial grass, reaching heights to about 12″. It is an  important sea grass in that it is a pioneer colonizer of disturbed areas where Turtle Grass and Manatee Grass cannot grow. It is often found in waters too shallow or too deep for other grasses to grow and can survive the widest range of salinity of all sea grasses. It can also survive direct exposure to air and tropical sunlight at low tide levels. Its popularity for use in the aquarium is growing, as it can do well in shallower substrates (3″ minimum) because the root system only extends about 4″ into the substrate. Just like other seagrass, the root system spreads by lateral growth of the rhizomes at their ends and is the most common form of reproduction. Sand beds that are rich in organic material are best, but plants can be fertilized by inorganic means such as dry and liquid plant food. As with Turtle Grass, there is evidence of the presence of nitrogen-fixing anaerobic microbes on their roots and rhizomes, which help to supply nitrogen to nearby grass beds. Free floating fragments remain viable for several weeks and can even repopulate sand beds. This characteristic makes it an ideal specimen for the aquarium as it is very hardy and adaptable. Most specimens find their way into the aquarium trade by the collection of “drift fragments” collected after storms and by boaters disturbing grass beds.

Scientific Name: Halodule wrightii

Common Name: Shoal Grass

Origin: Gulf of Mexico, Atlantic, Caribbean

Depth Collected: 1-6  Feet

Maximum Height : 12″

Growth Rate: Moderate

Light: High

Temperature: 65-86 Degrees

Propagation: Rhizomes, Seeds

Difficulty: Advanced

Food Value: Palatable to some fish

Nutrient Uptake: Good once established

Flow Rate: Moderate to High

Halophila engelmannii, more commonly know as Star Grass, is an interesting sea grass that is tolerant of cooler water temperatures. It is found growing in the waters of Florida, Louisiana, Mississippi and Texas. It features a tall upright that forms a cluster of 4-6 elongated leaves, resembling the algae Caulerpa paspaloides. Single plants grow to about 4-6″ tall. The root system spreads by lateral growth of the rhizomes at their ends and is the most common form of reproduction. Flowering is more productive in this species and it spreads throughout the ocean by the production of seeds. Sand beds that are rich in organic material are best suited for most sea grasses, but plants can be fertilized by inorganic means such as dry and liquid plant food. Overall, Star Grass is very hardy, requires only a sand bed of about 4″, and can be kept successfully with moderate to low lighting. It is rarely offered to hobbyists, but occasionally shows up in the aquarium industry when specimens can be collected.

Scientific Name: Halophila engelmannii

Common Name: Star Grass

Origin: Gulf of Mexico, Atlantic, Caribbean

Depth Collected: 4-100 Feet

Maximum Height : 6″

Growth Rate: Slow

Light: Moderate

Temperature: 68-82 Degrees

Propagation: Rhizomes, Seeds

Difficulty: Moderate

Food Value: Not Palatable

Nutrient Uptake: Good once established

Flow Rate: Low to Moderate

Halophila ovalis is a beautiful species of sea grass native to Asia and the South Pacific. It is commonly referred to a spoon grass or paddle weed. The plants grow from a single rhizome and prefer shallow, calm protected habitats but can be found as deep as 80 feet. Individual leaves grow to about 4″ with a rhizome of up to 2ft long. Halophila tolerate a large range of salinities ranging from 20 ppt. to 40 ppt. This particular species is not usually available to the aquarium trade in the United States, as it is an endangered plant, but is offered by some tropical fish exporters (mainly in the Philippines). Most species of Halophila prefer very organic, soft sand or mud bottom habitats. They are fairly easy to care for in the aquarium, as the root system is shallow, so can even be added to a well equipped refugium. As in all sea grass species, they prefer organic nutrients derived from the sand bed, so will do best in a properly “aged” sand bed and/or substrate.

Scientific Name: Halophila ovalis

Common Name: Spoon Grass

Origin: Indonesia, S. Pacific

Depth Collected: 1-80 Feet

Maximum Height : 5″

Growth Rate: Moderate

Light: High

Temperature: 72-86

Propagation: Rhizomes, Seeds

Difficulty: Moderate

Food Value: Not Palatable

Nutrient Uptake: Good once established

Flow Rate: Low to Moderate

Manatee grass is the second most abundant sea grass in most of the Caribbean, as well as in Florida. It features long, cylindrical leaves reaching heights of up to 20 inches in deeper water meadows. It is most often found growing intertwined with turtle grass, as it prefers deeper water habitats to about 60 ft. Manatee grass can withstand salinities as low as 20 ppt. to approximately 40 ppt. In the aquarium it requires a moderate depth of sediment (6-8″ minimum) for its deep rhizome network. The root system spreads by lateral growth of the rhizomes at their ends and is the most common form of reproduction (flowering is rare). Sand beds that are rich in organic material are best, but plants can be fertilized by inorganic means such as dry and liquid plant food. The roots are easily damaged, so care must be taken when planting this particular species in the aquarium. A tall tank is usually needed as individual plants can grow quite large. It can be difficult to find specimens for sale as all seagrass is protected in Florida and can only be harvested as free floating specimens.

Scientific Name: Syringodium filiforme

Common Name: Manatee Grass

Origin: Gulf of Mexico, Atlantic, Caribbean

Depth Collected: 5-60 Feet

Maximum Height : 20″

Growth Rate: Slow

Light: High

Temperature: 78-86

Propagation: Rhizomes, Seeds

Difficulty: Advanced

Food Value: Not Palatable

Nutrient Uptake: Good once established

Flow Rate: Moderate to High

H. decipiens features small, oval shaped leaves, with a white vein down the middle with 6-8 cross veins per blade. Individual plants grow to just 1″ wide by about 3″ tall. It grows attached to a single rhizome in 4-6″ of sediment. It is abundant in calm protected water, where it often forms dense meadows in substrate rich in organic matter. It is typically found at shallow depths, but has been reported in water 280 feet deep in some locations. This species has recently become popular for use in the aquarium and is becoming more available due to the propagation efforts of aquarists within in the United States. H. decipiens is only native to a select area in the state of Florida, mostly the Indian River Lagoon. It is highly protected, so collected plants must be found free floating as drift specimens. Like other varieties of Halophila, it is relatively undemanding in the aquarium, but needs moderate lighting and an organic substrate to grow. Because it can grow very deep, it can often do well in refugiums with high levels of organic nutrients and low light. Not palatable to fish.

Scientific Name: Halophila decipiens

Common Name: Oar Grass

Origin: Gulf of Mexico, Atlantic, Caribbean, S.Pacific

Depth Collected: 10-100 Feet

Maximum Height : 4″

Growth Rate: Slow

Light: Moderate

Temperature: 72-86

Propagation: Rhizomes, Seeds

Difficulty: Moderate

Food Value: Not Palatable 

Nutrient Uptake: Good once established

Flow Rate: Moderate to High