Below is the paraphrase of an article in the new issue of Coral Magazine that I have listed below and linked so that you can read the full story in Coral Magazine. This is some really important finding for aquarists to be aware of. Activated Carbon: New Research Finds Link to HLLE Breakthrough study solves one mystery of head-and-lateral-line erosion Ocean Surgeonfish, Acanthurus bahianus, with severe HLLE after exposure to dusty activated carbon. Jay F. Hemdal Curator of Fishes and Invertebrates Toledo Zoological Society Special Report to CORAL: Advance Excerpt from the July/August 2011 Issue Background: Head and Lateral Line Erosion (HLLE) is the name for a type of skin erosion that affects some species of marine fishes in captivity. It is occasionally referred to as Marine Head and Lateral Line Erosion (MHLLE) or Head and Lateral Line Erosion Syndrome (HLLES). A similar syndrome occurs in freshwater fishes, but the causes seem to be different, and that is usually termed, “Hole-in-the-Head†disease. HLLE typically begins as small pale pits around the fish’s eyes. These may develop into light colored lesions along the fish’s lateral line system, finally spreading onto wider areas of the body and sometimes involving the unpaired fins. Fish that develop severe lesions are usually permanently disfigured. At least 20 families of fish have been identified as having developed HLLE in captivity (Table 1). Not all species of fish show the same symptoms, and do not always develop lesions to the same degree (Hemdal, right, 2006). HLLE is not normally seen in fish in the wild, but there are two published photographs that bring this into question; one taken by Rudie Kuiter in the Cook Islands shows HLLE in a large Black Tang, Zebrasoma rostratum and another image taken by Tim Laman in Bali shows minor HLLE pitting in a juvenile Emperor Angelfish, Pomacanthus imperator. Causes of HLLE: To date, the cause(s) of this syndrome have not been identified in aquarium fish through published scientific study, although conjecture and informal studies abound. This report is based in part on a peer-reviewed study that will be forthcoming in the North American Journal of Aquaculture (Hemdal and Odum in-press). That paper evaluates the relationship between the use of activated carbon in aquariums and the development of HLLE in surgeonfish. The results of an additional dietary study, not part of the original research is included here, but that material is offered only as preliminary results as it was not peer-reviewed. In 2009, a survey was taken of 100 advanced aquarists who identified 25 suspected causes for HLLE in marine fishes. The majority of the survey participants believed that HLLE in marine fishes such as tangs and angelfish is caused by a dietary problem, notably deficiencies in vitamin C or low levels of highly unsaturated fatty acids. General stress caused by captivity also was cited as a major cause of HLLE. Other survey responses included stray electrical current, the use of copper medications, heavy metal toxicity, lack of sunlight, the use of activated carbon or the presence of a variety of chemical pollutants all as possible causes of HLLE. Viral and bacterial infections have also been implicated in causing this syndrome (Varner 1991, Hemdal 1989). The history of activated carbon use at the Toledo Zoo has shown a correlation between the use of lignite (coal-based) carbon and the formation of HLLE lesions in some fishes. Moving the fish to aquariums without carbon filtration sometimes caused the lesions to heal without additional treatment. Once carbon use at the facility was curtailed over ten years ago, cases of HLLE greatly diminished. Based on those preliminary observations, the Toledo Zoo funded this study, the objective of which was to demonstrate the relationship between carbon use and the development of HLLE. In turn, it is hoped that these results will allow marine aquarists to make more informed decisions regarding the use of carbon in their aquariums. (Read full article here...) Current Study: Three 120 gallon marine aquarium systems (two tanks per system) were established using typical home aquarium equipment and synthetic seawater. Live rock was utilized as the basis for biological filtration in all three systems. Thirty-five Ocean Surgeonfish, (Acanthurus bahianus) were evenly distributed among the three systems at the start of the study. One week after the fish arrived, 500 grams of unwashed lignite carbon was placed in a mesh bag and added to the filter sump of the first system. At the same time, 500 g of extruded pellet carbon was placed in a mesh bag and added to the filter sump of the second system. No carbon was added to the control system. Two months later, the carbon in the first and second systems was supplemented with an additional 500 grams of each variety. This carbon usage follows the recommendation made by Spotte (1979), of 1 gram of carbon per liter, changed every two months. (Read full article here...) Study results: Minor HLLE lesions were noted on two fish 20 days after the lignite carbon was added to the sump of their system. The lesions began to develop on the additional fish in that system, and grew in size until after four months, all of the fish in that system showed severe lesions (Eventually involving over one third of their body surface). One fish of this group died, but this was attributed, (at least in part) to tank mate aggression. (Specimen exposed to carbon with HLLE and overall health degeneration, right.) The 12 fish exposed to pelleted carbon did not develop visible symptoms, but microscopic lesions were discovered upon histological examination by an outside laboratory, and two of the fish developed minor lesions a few months after the conclusion of the study. The 11 control fish did not develop any visible or microscopic lesions. Six months after the study was concluded, and the carbon was removed, the HLLE lesions remain on all originally affected fish, and the control fish are all still symptom-free. The effect of lignite carbon on the fish was swift and involved all of the exposed fish. None of the control fish developed any lesions. Statistically, the results were definitive that activated carbon use caused HLLE in these fish. Read full advance article her [url2='Coral Magazine HLLE Article':1qgsvupb]Coral Magazine HLLE Article[/url2:1qgsvupb] If you do not subscribe to Coral Magazine I can tell you it is one of the best marine aquarist magazines on the shelf.  They have digital subscriptions as well as paper plus a new iPad app for their magazine that is just awsome. They have been a long time supporter of the club and hopefully will not be bothered by the reprint of this important article on our forums.
That's really interesting. I was thinking about GAC. I might think again. Sent from my Droid using Tapatalk
Rinsing my be ok but if carbon shifts new dust, I think the only way would be to not use it or to somehow run it thru another filter after carbon to make sure no dust makes it to tank
