Marine plants in a saltwater aquarium can help improve water quality and add biodiversity. The aquarist should determine if plants should provide a food source for the fish or deter fish and be left intact. Correct water flow, aeration and artificial lighting appropriate to both plant and fish can help ensure success.
Shaving Brush Plant
The shaving brush plant (Penicillus capitus) belongs to the family Bombacaceae. Shaped like a barber's shaving brush, these green macroalgae feature feathered, leaf-like forms on a long, tubular stalk with roots. Shaving brush plants originated in the West Atlantic or Caribbean. In its natural habitat, the shaving brush plant thrives in sandy, shallow water pools. This 2- to 4-inch plant is easy to care for and needs medium water flow. The saltwater tank should have a well-lit area where strong lighting reaches the tank bottom.
Encrusting corallines can form patchwork expanses over rocks, plants and mollusc shells. These algae form carbonate shells, produce nutrition for herbivorous or plant-eating invertebrates and indicate the health of the aquarium's ecosystem. In the natural habitat, this calcified pink crust occupies shaded areas, covering floor and walls of tidal pools in addition to moist rock surfaces. For the saltwater aquarium, the Corallinaceae species can add colors of pink, red, purple, green and white.
Turtle weed (Chlorodesmis fastigiata) belongs to the family Codiaceae. These emerald green, fuzzy algae feature thin filaments like grass blades. With a height of 6 inches and a diameter of 2 to 8 inches, turtle weed or maiden's hair, forms tufts or patches. Its natural habitat includes reefs and on rocks from low-tide to sub-tidal zones. It is found in Australia's coral reef of Queensland and New South Wales, Indonesia, Mozambique and Kenya. In the aquarium, these algae require a moderate to strong water current produced by a powerhead with a wave maker or surge device. Turtle weed secretes a toxic substance that deters grazing, plant-eating fish.
Red gracilaria belongs to the Gracilariaceae family. According to the University of South California, this reddish to purple algae appears translucent with few to many branches that may be brittle to rubbery. Blade diameters can range up to 1 inch long. In the wild, red gracilaria offers a food source for herbivorous fish. In the aquarium, these algae thrive when not disturbed by fish or invertebrates. Requirements include moderate flow and lighting for these attractive, feathery plants that reach up to 15 inches in height.
Sea lettuce (Ulva lactuca) belongs to the family Ulvaceae, edible green algae. The species "lactuca" refers to "lettuce." Sea lettuce features broad, sheet-like leaves that appear whole in oval or round shapes or divided with ruffled edges. Natural habitat includes rocks and shells and tide pools. Sea lettuce can float or live at a depth of 75 feet. It is beneficial to the aquarium in that it removes nitrate and phosphate from the water. According to the University of Rhode Island, these algae can live in levels of nutrient pollution, such as those from fertilizers and detergents. The sea lettuce's density and location can indicate pollutants that stimulate its growth. Saltwater aquarium requirements include moderate to high lighting and high water flow.