FREE ISSN 1045-3520 Volume 18 Winter 2001 The Conscientious Reef Aquarist: Photo by Tom Frakes Blue-Green Algae (Cyanobacteria) in Marine Aquaria by Robert Fenner Problems associated with blue-green algae account for a large number of requests for help that I receive over the Internet. I suspect that blue-green algae problems account for more loss of captive life than any other cause, excepting deaths resulting from ammonia problems. Blue- green algae are simple life forms, and easily defeated in aquaria. A discussion follows that describes what they are, why they are undesirable in an aquarium, and how to get rid of them. Classification Blue-green algae are more properly known as Cyanobacteria. Cyanobacteria and true bacteria are classified in the kingdom Monera. True algae are actually in the kingdom Protista, along with similar life forms. Although Cyanobacteria are not really algae, the distinction is a technical one, and many people continue to call them blue-green algae. Many species of blue-green algae that are encountered by aquarists are microscopic, but some forms resemble green filamentous algae. Colonies generally appear to be blue-black or reddish slimes, smears, or filamentous threads. Corals in Bali Barat National Park largely escaped bleaching in 1998. Environment Blue-green algae can be introduced into an aquarium in newly-added live rock, in water with livestock additions, in food, and even as 9th International Reef Degradation spores entering by means of the air supply. In Coral Reef Symposium Numerous papers concerned with reef general, they are more tolerant of fluctuations degradation discussed localized reef destruction in pH, temperature, and specific gravity than Report and the effects of temperature and pollution. One session, led by Dr. E. A. Shinn, considered the desired aquarium species. The best defense by Tom Frakes and Rand Kollman against too much blue-green algae is the effects of African dust on Caribbean reefs. Storms promotion of the stable conditions that favor This past fall we had the opportunity to in African deserts result in dust carried by the growth of true algae. Maintain good water attend the 9th International Coral Reef wind across the Atlantic to the Caribbean, quality by cleaning filters and making regular Symposium held on the island of Bali, Indonesia. northern South America, and the United States. water changes, thus eliminating as much as Every four years this conference brings together These clouds of dust contain iron, nitrogen, and possible organic and inorganic nutrients. This reef scientists, environmentalists, and phosphate which rain down on the reefs, should help to keep the nitrate level below 10 governmental representatives from around the fertilizing algae and stimulating algal blooms. In parts per million and the phosphate level below world to discuss the state of the world’s coral recent years the African deserts have increased in 0.5 parts per million. Of course, overfeeding is a reefs. For five days, each morning and afternoon size, resulting in an increase in the amount of prime source of the organic compounds that session was opened with a one hour plenary talk, dust, now estimated to be as much as a billion fuel blue-green algae. Be particularly careful to followed by several hours of scientific presenta- tons a year. In a recent study that compared air use only a minimum of liquid invertebrate and tions spread among fourteen separate rooms. quality in 79 U.S. national parks, the St. Johns gelatine-based frozen foods. These twenty minute presentations covered Island National Park in the U.S. Virgin Islands had topics ranging from coral physiology to reef one of the highest counts of particulates in the air. Lighting ecology to the social and political effects of reef Another presentation concerned the risk to The second most important consideration management practices. There were almost 2000 Caribbean reefs from increased African use of for algae in an aquarium, after water quality, is participants. Choosing and finding presentations fertilizers and pesticides. A common terrestrial lighting. Providing light that is adequate for each day was quite a job. We would like to fungus that causes aspergillosis in two sea fans growth of beneficial algae is the best way to highlight a few of the sessions we attended that was isolated from the African dust by J. Weir and discourage the growth of blue-green algae. A may be of interest to marine aquarists. his associates. It was also suggested that the Continued on page 4 Continued on page 3 ©2001 Aquarium Systems, Inc., Mentor, OH - Printed in U.S.A. sheet of 1200, 1500, 2000, and 2500 grade for only in a horizontal, back-and-forth direction. Refinishing a Working fifty cents each. I used Nova Light #2 and Make one stroke the length of the aquarium and Plexiglass Reef Heavy #3 Acrylic Scratch Polishes on the then reverse. The first few strokes will allow you outside surface to polish the plexiglass and to judge the best speed to use. If the inner Aquarium lubricate the magnet. They are available from magnet falls to the bottom of the aquarium be by LeRoy Headlee Novus Company, 800 548-6872, or from a sure to remove any sand or gravel before plastics wholesaler. continuing. Remove the inner magnet every few At Geothermal Aquaculture Research minutes and wash the sandpaper with fresh water Foundation we maintain about forty separate Procedure and clean paper towels. This will remove any systems for the study of ornamental coral The materials you will need include one gummy build up on the sandpaper. production. Each October we hold an pair of Twister® aquarium magnets, one tube of Add new sheets of 400 grade sand paper until international Reef Farming Seminar, and in thick gel super glue, a roll of soft paper towels, the entire inner surface is sanded and the September last year we knew we had to do a lot one bottle each of Nova Acrylic Heavy Scratch majority of the scratches removed. To add a new of cleaning before the seminar. I have a four year Polish and Light Scratch Polish, and one piece sheet on top of the old one, place four drops of old 150 gallon plexiglass reef aquarium in my each of 3M Imperial Wet or Dry sandpaper super glue on the old sheet and press the new office. Several days before the seminar a house grade 400, 600, 1200, 1500, 2000, and 2500. one in place. When it becomes clogged, pull it off painter decided to pitch in and help by cleaning Use the following procedure on a small, the old sheet and replace it. The 400 grade paper the tank. The internal glass cleaning magnet fell inconspicuous test section of your aquarium to will do most of the work and is the least into the gravel and trapped a sharp piece of sand. gain confidence and technique before polishing expensive grade. Move on to the 600 grade When he had finished helping, there was scarcely the entire front panel. paper, still using the heavy polish. After the 600 a section of the plexiglass that was not scratched. If you can dedicate the pair of magnets to this grade paper, wash the outside magnet in tap At this point, it was hard to remember that project, attach the sandpaper to the inside water and change to the fine scratch removing the painter was just trying to help. That reef magnet using four large drops of super glue. If polish. When you have finished with the 2000 contains over a hundred types of coral, and there you’re going to use the magnets later for cleaning grade paper you will see that the inner glass is was no way to tear down the system and remake aquariums, attach the first sheet of sandpaper polished. The final polish, with 2500 grade it before the seminar. I needed to find a way to with two strong rubber bands. Begin removing paper, is necessary if you plan to photograph polish the front inside surface of the aquarium the scratch by using 400 grade paper attached to the reef. Sand lightly in a random circular while the animals were in the aquarium, only the inside magnet and squeezing a two inch long pattern. Other-wise, the light will refract from inches from the front surface. line of heavy scratch polish on the felt pad of the the parallel grooves in the polished surface. I spent over a decade working as an antique outside magnet for lubrication. It is very Such refraction is not noticeable to the eye, refinisher to pay my way through college, and I important to remember to move the magnets but is obvious in a photo. understand how to polish surfaces. I had experience polishing the outside of the coral farming units with wet and dry sandpaper and a liquid plastic polish, but I couldn’t use the polish inside the aquarium because it would be toxic to the animals. I decided to use a pair of Twister ® magnetic aquarium cleaners with wet and dry sandpaper. The magnets were perfect for this job because they are thin and very strong. Sandpaper is graded by a number system. The larger the number the finer the grit. I started with 400 grade paper and ended with 2500 grade. Although a standard paint store will carry 400 and 600 grades, finding the higher grades may be a problem. My sister referred me to a hot rod body shop, where I was able to purchase a half T Meticulously blended to simulate natural ocean PUBLICATION INFORMATION water, Instant Ocean SeaScope® was created to present short, informative dissolves to a clear solution articles of interest to marine aquarists.