Cyanobacteria or blue green algae are the most predominant group of photosyn-thetic and prokaryotes. The cyanobacteria are presented in the widespread of natural environment such as lakes, rivers, and ponds and have different pigments like chlorophylls, phycocyanin, and phycoerythrin. Hence, the cyanobacteria are involved in photosynthesis process through aerobic as well as anaerobic conditions. The association of cyanobacterial mass found on the reservoirs are called as cyanobacteria bloom. The blooms were highly accumulated on the surface of aquatic system, which are enriched with biological wastes or nutrients like nitrogen and phosphorus. The cyanobacterial blooms are typically denoted during in the season of spring (Planktothrix spp.) or in season of late summer (Microcystis spp.). These cyanobacterial blooms may produce metabolically active chemical components called as cyanotoxins against different aquatic predators. It may be characterized into dermato, cyto, hepato, and neurotoxins. These toxins are produced either dangerous effects to aquatic organisms as well as human beings or as any therapeutically importance. In this study, such metabolically active toxin producing cyanobacterial blooms were identified. © 2024 Elsevier B.V., All rights reserved.