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Sometimes an inshore reef will merge with shallow beds of turtle grass, one of the very few true marine plants. These grassy beds provide an environment for seahorses, pipefish, damselfish, wrasses, and the young of some reef fishes, including butterfly-fish, as well as small crustaceans, mollusks and worms. The sea grass also provides forage for the rare dugong (Dugong dugon), or sea cow, which ranges across Indonesian waters.

Plankton

The diver will rarely see plankton, and if he or she does, it will usually be apparent as a cloudiness of the water, or an irritating backscatter in photographs. But plankton is an important link in the reef food chain. Reef areas rich in plankton will be characterized by an abundance of filter-feeders, animals that have evolved methods of sifting or snaring plankton from the current—including soft corals, mussels and oysters, anemones, crinoids, gorgonians and sponges.

Plankton consists of both "plants"—phytoplankton—and "animals"—zooplankton, and the larger zooplankters are predatory on the diatoms and algae of the phytoplankton. The plankton also contains some temporary members, the meroplankton, which consists of the larval stages of fish and invertebrates. As these grow, they settle out of the plankton stream to become part of the swimming nekton (fish, jellyfish) or the crawling or fixed benthos, or bottom dwellers (sea urchins, gorgonians).