This review explores advancements in biological strategies for controlling harmful algal blooms (HABs). HABs, primarily driven by phytoplankton like cyanobacteria, thrive in nutrient-rich, warm, and low-wind environments, posing threats to aquatic ecosystems, public health, and the economy. Traditional chemical and physical methods for HAB control are often ecologically risky and resource-intensive. Biological strategies, including biomanipulation and the use of algicidal microorganisms such as Streptococcus thermophiles, Myxobacteria, and Lopharia spadicea, offer eco-friendly alternatives with long-term benefits. Additionally, the application of barley and rice straw has shown efficacy in curbing HAB growth by inhibiting algal proliferation, disrupting cellular structures, and promoting algal cell aggregation. Biological control methods, such as the use of viruses, protozoa, and bacteria, have demonstrated potential in targeting specific algal species. Bacteria, in particular, play a crucial role in regulating phytoplankton biomass in freshwater environments. They can inhibit photosynthetic electron transport reactions and the activities of glycolate dehydrogenase and nitrogenase, contributing to the decomposition of algal blooms. Fungi, such as Trametes versicolor F21a, Bjerkandera adusta T1, and Lopharia spadicea, have been observed to attack HABs directly by releasing bioactive substances that disrupt algal cell integrity and photosynthesis. Zooplankton and fish contribute through grazing, aiding in the removal of invasive species and benefiting both fish and zooplankton. Algae, mainly through flocculation, have shown potential for bloom control, with golden algae identified as mitigators of Microcystis cells and toxin degraders. Despite their advantages, biological controls face challenges, including intricate ecological interactions and the need for large-scale production and application of microbial agents. The review highlights the need for further research and development in this critical area of environmental science. The article discusses the latest biological techniques aimed at eradicating HABs, intending to diminish their frequency and reduce toxin levels in aquatic environments. While most research has been confined to laboratory settings, scaling these methods to field applications presents hurdles due to the variability and complexity of natural ecosystems. The review underscores the importance of integrating various biological factors with a distinct life cycle into an ecological setting, posing considerable challenges. The article explores the ongoing problem of HABs, investigating their adverse effects on aquatic ecosystems and the challenges they present. While various strategies have been proposed to mitigate HABs, the focus is on physical, chemical, and recent advancements in biological methods. These innovative approaches aim to reduce the occurrence of HABs and effectively lower toxin levels in aquatic environments. The potential of microbial agents, viruses, fungi, zooplankton, fish, and algae in combating HABs is highlighted, emphasizing their ecological significance and potential benefitsThis review explores advancements in biological strategies for controlling harmful algal blooms (HABs). HABs, primarily driven by phytoplankton like cyanobacteria, thrive in nutrient-rich, warm, and low-wind environments, posing threats to aquatic ecosystems, public health, and the economy. Traditional chemical and physical methods for HAB control are often ecologically risky and resource-intensive. Biological strategies, including biomanipulation and the use of algicidal microorganisms such as Streptococcus thermophiles, Myxobacteria, and Lopharia spadicea, offer eco-friendly alternatives with long-term benefits. Additionally, the application of barley and rice straw has shown efficacy in curbing HAB growth by inhibiting algal proliferation, disrupting cellular structures, and promoting algal cell aggregation. Biological control methods, such as the use of viruses, protozoa, and bacteria, have demonstrated potential in targeting specific algal species. Bacteria, in particular, play a crucial role in regulating phytoplankton biomass in freshwater environments. They can inhibit photosynthetic electron transport reactions and the activities of glycolate dehydrogenase and nitrogenase, contributing to the decomposition of algal blooms. Fungi, such as Trametes versicolor F21a, Bjerkandera adusta T1, and Lopharia spadicea, have been observed to attack HABs directly by releasing bioactive substances that disrupt algal cell integrity and photosynthesis. Zooplankton and fish contribute through grazing, aiding in the removal of invasive species and benefiting both fish and zooplankton. Algae, mainly through flocculation, have shown potential for bloom control, with golden algae identified as mitigators of Microcystis cells and toxin degraders. Despite their advantages, biological controls face challenges, including intricate ecological interactions and the need for large-scale production and application of microbial agents. The review highlights the need for further research and development in this critical area of environmental science. The article discusses the latest biological techniques aimed at eradicating HABs, intending to diminish their frequency and reduce toxin levels in aquatic environments. While most research has been confined to laboratory settings, scaling these methods to field applications presents hurdles due to the variability and complexity of natural ecosystems. The review underscores the importance of integrating various biological factors with a distinct life cycle into an ecological setting, posing considerable challenges. The article explores the ongoing problem of HABs, investigating their adverse effects on aquatic ecosystems and the challenges they present. While various strategies have been proposed to mitigate HABs, the focus is on physical, chemical, and recent advancements in biological methods. These innovative approaches aim to reduce the occurrence of HABs and effectively lower toxin levels in aquatic environments. The potential of microbial agents, viruses, fungi, zooplankton, fish, and algae in combating HABs is highlighted, emphasizing their ecological significance and potential benefits