Activated Carbon might be a possible source for Head and Lateral Line Erosion (HLLE) to appear in fish that is according to a recent article in Coral. “HLLE is the name for a type of skin erosion that affects some species of marine fishes in captivity.” A history case from 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.” The Toldeo Zoo commissioned this study so that aquarists everywhere understand the effects of activated carbon and possible causes of HLLE. Feel free to hit the read link below to read the very interesting article.