Species Name: Derbesia marina

Authority: Solier, A.J.J. (1846)

Common Name: Hair Algae

Range: Tropical & Temperate Atlantic and Pacific Oceans

Natural Environment: Its wide spread in the wild and usually found in nutrient rich rook pools, shallow tidal flats, and protected intertidal areas with little water movement.

Aquarium Suitability: There are numerous types and colors of algae that are referred to as hair algae. Probably the two of most interest are Derbesia and Bryopsis. These two green filamentous hair-like growths are considered a major pest. Both are presently being considered cyanobacteria that contain chlorophyll. The first and most difficult of the two to overcome is a true hair-like growth called Derbesia. Its long, soft, and hair-like strands can rapidly cover wide areas. Not only can it become somewhat independent of bulk water nutrients once established, trapped detritus/debris can add further nutrients to the bulk water.

The other hair-like alga is Bryopsis plumosa. Its feather-like and upright growing structure occurs as a single stem-like plant with multiple long plume-like tufts. It also can become somewhat independent of nutrients from the surrounding bulk water once the plant structure becomes recognizable.

Both Derbesia and Bryopsis plumosa have two life cycles, i.e., as a small bubble-like growth and that of an easily recognizable plant-like structure. Derbesia has tiny spore packages called "sporangia" that form along its hair-like strands. When these packages mature, they burst open and release spores that settle and grow into "gametophytes" which look like small green bubbles. When these bubbles mature, they release male or female germ cells that eventually unite and form a "zygote," which is the base unit for the growth of a new structure of hair algae. Though some aquarists say algae does not grow on surfaces covered with coralline, that is not true. Quite frequently the early stage bubbles of Derbesia can be found attached to surfaces covered with coralline in the genera Sporolithon and Hydrolithon.

Potential Control Species: Fish: Acanthurus achilles, Acanthurus japonicus, Acanthurus leucosternon, Acanthurus lineatus, Acanthurus olivaceus, Acanthurus pyroferus, Ctenochaetus hawaiiensis, Ctenochaetus striatus, Naso brevirostris, Naso lituratus, Zebrasoma desjardinii, Zebrasoma flavescens, Zebrasoma scopas, Zebrasoma veliferum, Zebrasoma xanthurum, Ecsenius bicolor, Ophioblennius atlanticus, Siganus corallinus, Siganus guttatus, Siganus magnifica, Siganus vulpinus, Centropyge acanthops, Centropyge argi, Centropyge aurantius, Centropyge bispinosus, Centropyge eibli, Centropyge fisheri, Centropyge flavissima, Centropyge heraldi, Centropyge loricula, Centropyge nox, Centropyge resplendens, Centropyge shepardi, Centropyge vroliki, Amblygobius hectori, and Amblygobius rainfordi.

Crabs: Clibanarius tricolor, Paguristes cadenati

Sea Hares: Aplysia californica

Sea Slugs: Elysia diomedea, Elysia ornata, Tridachia crispata

Snails: Astraea tectum, Trochus niloticus, Turbo fluctuosus, Strombus alatus, Strombus gigas

Urchins: Diadema setosum, Mespilia globulus