Aquarium fish gill disease — parasites, bacteria, and environmental causes
Source: Merck Veterinary Manual (merckvetmanual.com), a copyrighted professional veterinary reference. Per COPYRIGHT_POLICY §3, the points below are paraphrased derived fact summaries: numerical values and proper nouns are preserved from the source, but sentences are rewritten and not quoted verbatim.
Claims
*[Paraphrased derived summary — non-Open-Access source.]* Divalent ions are excreted mainly by the kidneys, and monovalent ions and nitrogenous wastes via the gills. *[Paraphrased derived summary — non-Open-Access source.]* Therefore, kidney or gill lesions can seriously disrupt respiration, excretion, and fluid balance. *[Paraphrased derived summary — non-Open-Access source.]* A gill biopsy can be taken, but the fish should be returned to water briefly (30 seconds to 1 minute) before the next procedure.