Modular Nanobubble Generator is a compact, plug-and-play device that improves water quality, hygiene, and crop productivity by injecting nanobubbles into water systems using gases such as oxygen, carbon dioxide, nitrogen, and hydrogen. Designed for easy integration into existing piping, the system requires no rotating or electrical components. Multiple modules can be linked together to scale capacity. Nanobubbles are produced using a patented silicone nanotube with a structured friction surface. This method delivers high gas solubility with minimal power consumption. Applications include aquaculture, smart farming, and wastewater treatment. The system raises dissolved oxygen, reduces pH without chemicals, and suppresses microbial growth. Operators can adjust gas and pressure manually or add sensors for automated control. A sight glass and pressure gauge provide real-time visual feedback. The system is built from corrosion-resistant materials and is designed for long-term durability in harsh environments, with minimal maintenance needs.