Good article from: http://www.marineland.com/seascope/ss2003_issue3.pdf --- Asparagopsis taxiformis: A troublesome reef algae By Michael P. Janes In the past, the thought or mention of algae was something that conjured up concern, emotion, and even fear in some marine aquarium hobbyists. Today, most modern coverage on the topic of algae emphasizes the important role they play on a healthy coral reef and how they may do the same in your tank. A relationship exists on coral reefs between algal growth, nutrient processing, and grazing. Nuisance algae in aquaria can be the result of a change in the pathways by which nutrients are processed. These changes can be subtle and difficult to detect. By the time a problem occurs it can be too late for any kind of rapid correction. Another important component of algae control in aquaria is herbivore diversity. Typically excessive algae growth is the result of an insufficient variety of algae consuming animals and/or excessive nutrients. Even among reef keeping hobbyists who are well aware that over feeding and insufficient water changes can contribute to algae problems, and who diligently do maintenance and routine testing occasionally an algae can appear that defies conventional reasoning and solutions. Such is the case with the red hair algae, Asparagopsis taxiformis. The genus Asparagopsis contains two species A. taxiformis and A. armata. They belong to the red algae division Rhodophyta that has about four thousand described marine species. Examining the branches in sexual forms at medium magnification can separate the two species of this genus. As its name suggests the species A. armata has small spines on the branches. Asparagopsis taxiformis has smooth branches. Red algae have the most elaborate lifecycles of all the marine algae. Successive generations alternate between an asexual sporulation stage and a sexual stage composed of male and female plants. The physical appearance of these two stages is quite different making identification difficult at times. Early investigations into the species A. taxiformis initially lead to its asexual stage being classified as a different species! The characteristic red color in the Rhodophyta is the result of a water-soluble pigment called Phycoerythrin. This pigment not only reflects light but also absorbs and converts it to a narrow band which it reemits as a fluorescing red color. Phycoerythrin also assists in photosynthesis by making light usable at low intensities. Aquarium Observations Asparagopsis taxiformis is typically introduced into aquaria attached to the substrate of coral specimens. Cured or uncured live rock does not seem to harbor these algae, suggesting that it is not usually associated with fish only tanks but rather reef aquaria. It initially appears as small tuffs or balls growing to about one inch in diameter. They are soft to the touch and are comprised of thin, segmented threads that break apart easily. Once present, this insidious alga usually spreads quite rapidly. It is often epiphytic and will attach to almost any available surface including the fronds of macro-algae, sand, coralline covered rocks, and even corals where any skeletal portion is exposed. Fortunately this alga does not cause direct harm to corals resulting from any chemical secretions or allelopathy. It will, however, shade corals and also create a barrier that prevents coral tissue from being exposure to passive water flow. Both of these events ultimately produce ill effects on corals. Environmental conditions such as light and water chemistry would be the typical troubleshooting areas to investigate. Unfortunately, no direct link has been found to indicate lighting or a particular water parameter was to blame. Examination of parameters from a number of aquaria showed that Asparagopsis taxiformis can grow in low light refugia, brightly illuminated reef aquaria with metal halide and/or power compact lighting, and even dark sumps. Water chemistry of the systems tested revealed no abnormal parameter. Nutrients were low with orthophosphate levels reading 0 parts per million (ppm) and nitrate 0 to 10 ppm in various aquaria tested with low range test kits. Kalkwasser will often reduce the abundance of unsightly filamentous algae and may also assist in the control of these red algae over time. It is used as a means to encourage encrusting coralline algae to flourish and at the same time bind orthophosphate. Iodine tests on a number of systems revealed levels that were most often 0 or did not exceed 0.06 ppm, which is near natural seawater concentrations. Interestingly, Codmier et. al. (1979) working on Asparagopsis armata found that iodine levels of 0.6 ppm provided the most rapid growth in this algae species. Growth was inhibited when concentrations of iodine were increased above 1.8 ppm. Control of Asparagopsis The first line of defense is prevention. Carefully inspect the substrate of new corals and even live rock for signs of the red hair algae. Consider placing new specimens in a quarantine tank for the first one to two weeks. Not only will this quarantine period reveal the unwanted algae but it will also allow time for the coral to be monitored, feed, and given a period to adapt to captive conditions. Unfortunately for the reef aquarist the most common herbivores offered for sale do not rapidly consume this algae. A number of algae eating fish and invertebrates were rotated through a large tank with an outbreak of Asparagopsis taxiformis. These included the rabbitfishes Foxface (Lo vulpinus), and Gold-saddle (Siganus guttatus), Yellow Tangs (Acanthurus flavescens), Desjardini Tang (Zebrasoma desjardinii), the Lawnmower Blenny (Salaris fasiatus), and a number of invertebrates such as the Sally Lightfoot Crab (Percnon gibbesi), Emerald Crab (Mithraculus sculptus), Blue leg reef hermit (Clibanarius tricolor), Red leg reef hermit (Calcinus tibicen), a Sea hare (Elysia sp.), and a variety of snails from the Atlantic. None of these animals were observed to consume enough of the algae to overcome its prolific growth. Fortunately there are two ways to control a case of excessive red hair algae. The first is the least effective and that is manual control. In essence, the hobbyist becomes the “grazer” and physically removes the tuffs of algae from the aquarium. The best a hobbyist can hope for is a stalemate where the problem algae do not get much worse, but it remains an unsightly presence in the aquarium. Perhaps a more realistic solution is in finding a grazing organism that has a taste for Asparagopsis. Such is the case with the Pacific Turbo Snail, Turbo fluctuosus. It finds red algae very palatable and preferable to other green and brown micro-algae. This species should not be confused with another turbo snail sold in the hobby, Astrea tectum from the Caribbean. Ten Pacific Turbo Snails can typically be supported in a fifty-five gallon aquarium where micro and filamentous algae are present. Patience is a key component in controlling an outbreak of any algae. It is more important to maintain a more diverse assemblage of herbivores than to keep too many of one kind. Certainly there are bound to be other grazers out there that feed on Asparagopsis taxiformis and other red algae. But many are not regularly available in the trade. Thus far the Pacific Turbo Snail appears to be the best solution for marine aquarists. Conclusion Algae will always be present in aquaria and their control is combination of minimizing excessive nutrients, maintaining water quality and having a diverse population of herbivores. Eventually a state of equilibrium will be reached which is unique to each tank where algae growth will be matched by algae consumption. By carefully inspecting new specimens and maintaining a variety of herbivores (particularly the Pacific Turbo Snail) Asparagopsiswill be just one more interesting life form to be observed and identified in the amazing microhabitats we keep rather than a pest. Acknowledgments I would like to thank the kind assistance of Dr. Allan Miller, Royal Botanic Gardens, Sydney, Australia, and Dr. D. Wilson Freshwater, Center for Marine Science, University of North Carolina, Wilmington for help in identification of the algae pressing. I also appreciate the project support offered by Scott Davidson, Sandy Shoup, Dr. Ronald Shimek, and AquaTouch, Inc., Phoenix, Arizona.