I've seen similar studies that support this. In years long past, I used charcoal and GAC but, such studies not being available, I never made a connection to any fish problems. Have you seen any explanation for the effect? I'm wondering if it is a particular critical component being removed from the water or if it is something that leaches from the GAC.
What cichlids did you have when used activated carbon?
How often did you use?
How long did you have these cichlids?
The underlying cause of FHLLE (freshwater version) and MHLLE ( marine version) have, in fact, not been determined. If activated carbon has been eliminated as a possible cause I have not yet read the definitive study/studies. If anyone has come across this in a scholarly/science- based journal I would be happy to read it.
One of the most up-to-date manuals on fish pathology and diagnosis is Edward J. Noga M.S., D.V.M. ( 2010). In his book Fish Disease: Diagnosis and Treatment
he states that:
[Lateral Line Depigmatation] has been linked to many possible etiologies" (
2010 p. 333).
He then goes on to list these etiological possibilities based on findings from scientific studies: diplomonad flagellates, a reovirus, mineral imbalance ( Vitamin C is what Noga cites) due to effects of the prior two microbes, water quality, and activated carbon. He quotes Stampers study ( 2009 link above) stating that :
"... there is evidence that either ozonation or certain types of activated carbon can induce LLD in marine fish" (
2010 p. 335).
I am attaching a link ( a quick one page outline) that provides a good overall outlook of possible etiologies still being examined as possible causes of HLLE:
Clinical Veterinary Advisor - E-Book: Birds and Exotic Pets
By Joerg Mayer, Thomas M. Donnelly