Background : Obvious applications of aloe (Aloe vera) and their rapid intake make it crucial to evaluate their biological impacts to aquatic organisms. Methods and Results : In this study, we investigated the possible effects of aloe extract on zebrafish embryos (Danio rerio) by assessing teratogenic properties including survival rate, hatching success, heart rate and morphological changes for 96hpf (hours post fertilization). We noticed that exposure to aloe extracts (0.1, 10, 50, 100 and 150 μl/ml in embryo medium) to zebrafish embryos showed no alterations in survival and morphological changes when compared to control embryos. In contrast, embryos exposed to 150 μl/ml of aloe extract shows delayed hatching rate at 72hpf when compared to lower concentrations. Similarly, aloe extract at 150 μl/ml exposed embryos elicited significantly reduced heart rate (132 ± 1 beats/min) at 48hpf when compare to control embryos. Conclusion : Based on the above findings, we speculate the teratogenic effect of aloe extract on zebrafish embryos.