High Mortality in XXXX ( @entity3392 ).

@entity295 @entity548 @entity3265 @entity1066 @entity3542 @entity1678 @entity3392 @entity1319
A group of 100 adult @entity3392 were housed in a new system at a stocking density of 20 fish per tank. Four weeks after arrival, 15 fish presented with @entity548 and @entity1066 on the surfaces of the skin. Samples of the fish were collected for histopathology, fungal culture, and bacterial culture and sensitivity. Water samples were analyzed for pH, @entity3265 , @entity3542 , and submitted for bacterial and fungal culture. Histologically, the epidermis had multiple areas of @entity1066 and mononuclear cell infiltrate. Gram-positive bacteria were observed beneath the surface of the skin and surrounding the outer aspect of the spinal cord. Both @entity1678 and A. sobria were isolated from the affected fish, and a diagnosis of @entity1319 ( @entity1319 ) was made. Water from the tanks had a @entity3542 level of 1-5 ppm, a toxic concentration that indicated poor water quality. Because the housing system had been seeded with Nitrobacter spp. and Nitrosomonas spp. only 2 weeks prior to the arrival of the fish, a lack of colonizing nitrifying bacteria was deemed to be the cause of the high @entity3542 level, which, along with over-crowding, stressed the fish and increased their susceptibility to @entity1319 . No further cases of @entity295 were observed once the @entity3542 level and stocking density were reduced.
