Graceful, hypnotic, and utterly unlike any other aquarium species, jellyfish have captured the fascination of aquarists and nature lovers around the world. Their slow, pulsating movements, soft translucence, and ethereal glow make them living art forms that transform any space into a serene underwater world. Yet behind their beauty lies one of the most delicate and demanding forms of marine husbandry. Jellyfish Keeper’s Handbook is the definitive guide for anyone captivated by these remarkable creatures and determined to understand the science and art of keeping them healthy in captivity. This comprehensive manual takes readers on a journey from the fundamentals of jellyfish biology to the intricate techniques of aquarium setup, feeding, breeding, and long-term care. It begins with a clear introduction to the natural history and physiology of jellyfish—explaining how their anatomy, life cycle, and behavior shape every aspect of their husbandry. Readers will gain insight into how jellyfish move, feed, and respond to their surroundings, developing the knowledge necessary to recreate their ideal environment. The book then explores the practical side of jellyfish keeping in meticulous detail. It explains how to design, build, and maintain a jellyfish aquarium, focusing on Kreisel and pseudo-Kreisel systems that ensure proper water flow and circulation. Essential aspects such as water chemistry, filtration, lighting, and temperature regulation are thoroughly covered, providing a foundation for both beginners and experienced marine enthusiasts. From acclimation techniques to precise feeding routines, each step is written with clarity and depth to help readers avoid common pitfalls and maintain stability in their systems. Beyond the basics, Jellyfish Keeper’s Handbook delves into advanced topics rarely addressed in hobbyist literature, including breeding and life cycle management, disease prevention, ethical sourcing, and the challenges of maintaining sustainable captive populations. The book emphasizes responsible keeping practices and offers guidance on how to balance aesthetic ambition with biological integrity. For those inspired by the meditative beauty of jellyfish, this guide also includes a section on lighting design and display artistry. Readers will learn how to use illumination, color, and movement to create calming, immersive aquariums that serve as both scientific exhibits and works of living art. The book also addresses compatibility concerns, explaining why most jellyfish thrive best in dedicated systems and offering creative alternatives for mixed or companion displays.