Acid-fast bacterial infection and its control in guppies (Lebistes reticulatus) reared on an ornamental fish farm in Venezuela

There was a spontaneous outbreak of mycobacteriosis in fancy veiltail guppi es, Lebistes reticulatus, raised on an ornamental fish farm in Venezuela. T he clinical signs included listlessness, emaciation, spinal curvature, sunk en eyes and loss of colour. Numerous acid-fast bacteria, identified as Myco bacterium species, were detected in smears from the kidneys, liver, mesente ry and spleen of the fish, from fresh faecal material, and from the unborn embryos of infected gravid females. The bacteria were eradicated by the add ition of kanamycin sulphate to the water at a concentration of 50 ppm, the dose being repeated on four occasions with 48 hours between each dose. Fift een days after the treatment, none of the clinical signs described were det ected in any of the treated fish. The offspring born to treated females wer e healthy and normal, and did not harbour acid-fast bacteria.