ABSTRACT
This study assessed the adverse effects of aquarium - acidity [pH = 4] on the histology and ultrastructure of the liver of the lover of the catfish, Clarias lazera after 2, 5 and 7 days of exposure. In fish inhabiting the acidified water for 2 days, venous congestion was prevalent in the liver tussue and liver cell cytoplasm became glassy and less eosinophilic. The nuclei of such cells displayed dense basophilic stainability. In fish inhabiting acidified water for 5 days, paraffin sections of the liver showed lymphocytic infiltration. The hepatocytes displayed mottled stainability and a number of vacuoles appeared in the cytoplasm of some liver cells. Some liver cells were necrotic, lysed and their nuclei displayed deformity or pyknosis. Ultrastructurally, some mitochondria became elongated and displayed irregular contours. The endoplasmic reticulum showed mild fragmentation. Increased fat vacuoles of different sizes appeared in the cytoplasm. Some liver cell nuclei were deformed. In fish inhabiting acidified water for 7 days, paraffin sections showed that some liver cells were severely dissociated, lysed and necrotic. A number of liver cell nuclei were deformed or pyknotic. Lymphocytic infiltration and venous congestion were pronounced. In electron micrographs of the liver,certain areas of the cytoplasm of the liver cells were electron - lucent and structureless. The endoplasmic reticulum was severely fragmented into large number of small vesicles. Besides the increased fat vacuoles, the ground cytoplasm showed hydropic degeneration and the mitochondira exhibited bizzare shapes