Comparative Morphology and Morphometry of Blood Cells in Zebrafish (Danio rerio), Common Carp (Cyprinus carpio carpio), and Tilapia (Oreochromis niloticus)

Several diagnostic tools are available for veterinarians and fish health professionals to evaluate fish health and their abnormalities. However, reference data regarding the character and size of fish blood cells are limited. The purpose of this study was to analyze the morphology and morphometry of normal blood cells in zebrafish (Danio rerio), common carp (Cyprinus carpio carpio), and tilapia (Oreochromis niloticus). To get a representative sample, we took blood from ten 6-mo old healthy fish from each species. Fish were purchased from an ornamental fish market and the local government fish breeding center in Yogyakarta, Indonesia. A total of 100 erythrocytes and a maximum of 30 leukocytes (neutrophils, eosinophils, basophils, lymphocytes and monocytes) were randomly sampled and analyzed qualitatively and quantitatively, including morphometric analysis of both the long axis (LA) and short axis (SA) of these cells. All data obtained were analyzed using ANOVA statistical tests to compare the blood cells in each species with SPSS software. The findings revealed distinct differences in both morphology and morphometry of the blood cells among the species. Basic knowledge obtained from this research will aid in the development of biomarkers and other ancillary diagnostic tools for further hematology research, conservation, and clinical diagnosis in these 3 fish species.