Acute Toxicity of Clove Oil and Effects on Histopathological Changes in Gill of Siamese fighting Fish Betta Splendens

The effects of clove oil on the Siamese fighting fish Betta splendens were studied The estimated LC50 at 96h of clove oil for acute toxicity test was 26.3 ppm. Clove oil was effective as sedative and anesthetic dosages at concentrations of 5 to 20 ppm and 30 to 50 ppm respectively within 48 hours. Histopathological studies of the gills showed that epithelium edema of secondary lamellae, hyperplasia of epithelial cells, epithelial lifting, secondary lamellae fusion, contracted pillar cells, dilated sinus spaces and necrosis were present at concentrations from 15 to 40 ppm. The highest degeneration was found at the anesthetic stages of clove oil. These data are valuable for the early recognition of toxicity from clove oil in Thai fish. The knowledge of this study can be used to determine the suitability and safety of using clove oil in Betta splendens transport.