By Michael P. Janes

(Originally published in SeaScope vol.20 (3), 2003)

to algae problems. Even with diligent 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.

Rhodophyta

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 armata have 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 taxiformis initially lead to its asexual stage as being classified as a different species!

The characteristic red color in the Rhodophyta is the result of the water-soluble pigment Phycoerythrin. This pigment not only reflects light but also absorbs and converts it to a narrow band that 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 aquariums 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 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 trouble-shooting areas to investigate. Unfortunately no direct link was found to indicate lighting or a particular water parameter was to blame. Examination of parameters from a number of aquariums showed that Asparagopsis taxiformis can grow in low light refugiums, brightly illuminated reef aquariums with metal halide and power compact lighting, and even dark sumps. Water chemistry of the systems tested revealed no abnormal parameter with nutrients such as phosphate and nitrogen levels reading zero in the case of phosphate and zero to ten parts per million nitrates 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 phosphates making them unavailable to soft hair algae. Iodine tests on a number of systems revealed levels were most often zero and did not exceed zero point zero six parts per million, which is near natural seawater concentrations. Interestingly, Codmier et al (1979) working on Asparagopsis armata found that iodine levels of zero point six parts per million provided the most rapid growth in this algae species. Growth was inhibited when concentrations of iodine were increased above one point eight parts per million.

Control

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 aquariums and their control is simply a matter of minimizing excessive nutrients and maintaining 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 that include the Pacific Turbo Snail then, if Asparagopsis is encountered it will be just one more interesting life form to be observed and identified in the amazing microhabitats we keep.

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.

Text Box: Herbarium Press

Reef aquarium hobbyists are consummate collectors. Whether it is equipment and spare parts, books, or even logs of their tanks history the accumulation of aquarium materials is almost inevitable. Many hobbyists will even hang on to coral skeletal samples or clamshells from previous inhabitants of their tank. It is both possible and advantageous to preserve algae samples as well. Preserved algae specimens offer a hard copy record of the types encountered over the lifetime of a tank. Preservation is also a convenient way to help identify a particular type of algae by taking it to a local aquarium shop, photographing it, or sending it off to a university or museum. A simple herbarium press can be built to dry algae samples. The procedure for soft, fleshy algae is as follows.

To prepare the samples for drying remove them from the formalin fixative and gently rinse them in a little saltwater. Inspect the algae for any bits of substrate or sand and remove excess debris at this time. Three and a half by five-inch cards can be cut from waterproof, acid free paper and be used to mount the specimens. This kind of paper can be obtained from aquaculture supply sources. Larger or smaller cards can be made depending on the size of the samples and how they will be stored. Place the cards in a shallow bowl containing RO/DI water. Using forceps or an artists paint brush spread out the algae samples in the bowl over the cards. Gently lift the cards out of the water at a low angle. This will cause the water to run off of the cards away from the algae and help to spread the branches in a single layer. Cards should be placed on a paper towel to absorb excess water.

 

 

 

 

 

 

Pressing the samples is both easy and inexpensive. Cut pieces of corrugated cardboard, cheesecloth, and wax paper six or seven inches square. Crumple wax paper so it is wrinkled and has an uneven surface and lay it on top of the algae cards. Next lay a few squares of cheesecloth down then follow with a few pieces of paper towel. For multiple samples, just palace a piece of the cardboard between each layer and repeat the procedure. Bundle this package between two squares of corrugated cardboard and strap together with a few taunt rubber bands. Place a brick or other heavy object on top of the press and store in a warm dry place. Check the pressing daily and replace paper towel pieces as needed. It may take a week or more for the samples to completely dry. Once complete check the algae to see if it has remained attached to the paper card and if not, tack it in place with a few drops of hard setting glue. The finished pressing should be labeled. It can then be stored in a transparent sleeve like those used to hold photographs.

References

Codmier, L., et al. 1979. Effects of iodine on the growth of the fronds of Asparagopsis armata (Rhodophyceae, Bonnemaisoniales) in culture from spear bearing branches. Giornale Botanico Italiano 113 (5-6): pp 387-393.

Dawes, C. J. 1998. Marine Botany. John Wiley & Sons, Inc. New York, N.Y. 480 pp.

Fossa, S. A., and Nilsen, A. J. 1996. The Modern Coral Reef Aquarium. Vol. 1. Birgit Schmettkamp Verlag. Bornheim, Germany. 367 pp.

Silva, P. C., Basson, P. W., and Moe, R. L. 1996. Catalogue of the Benthic Marine Algae of the Indian Ocean. University of California Press. Berkeley, California. 1259 pp.

Sprung, J. 2002. Algae: A Problem Solver Guide. Ricordea Publishing. Miami, Florida. 80 pp.