Observation of Epistylis Disease in colour carp

Abstract

The colour carp with the so-called Epistylis Disease which were sent from Niigata Colour-Carp Research Institute to our laboratory were submitted to study the causative organism and the way of treatment.
Red spots and / or supprative wounds amounted to 5 or more per fish were present on the body surface of the diseased fish. The red spots showing haemorrhagic swelling were 5-20 mm in diameter size. A large number of rod bacteria was present in all of the wounds, and also water molds and Epistylis like bell animalcula were found in several wounds, occasionally. Two strains of gram-negative bacteria (strain A and B) which were virulent to goldfish were isolated from the wounds. The strain A, Aeromonas like, was a major bacterium, and the strain B of a minor bacterium differed from the member of Aeromonas or Vibrio. Both strains were sensitive to nifurpirinol, and rather resistant to tetracycline and malachite green.
The majority of red spots and wounds disappeared within 7 days following the continued bathing in 0.05 ppm of nifurpirinol. From the results obtained, it was considered that Aeromonas like bacterium participated as a causative organism in this case.