Mineral Rocks - Doubles The Survival Chances of Fry - Boost Immunity, Stronger & Larger Fins with Improved Parasite-Resistance by Providing Calcium - Absorb Toxic Chemical & Stabilize pH in Water PROVIDES SAFE ENVIRONMENT FOR FISHES TO LIVE, MATE & BREED --- With their textured surfaces, rounded edges and subtle earth tones, SunGrow mineral rocks create the look and feel of fishes natural habitats, providing a safe and stimulating environment in which to live, mate and breed. IMPROVED COLOR, HEALTHIER SKIN, SKALES & SKELETAL SYSTEM --- Multifunctional, and economical, the health booster rocks nourish, cure, and cleanse the aquarium fish. Every pack contains a few pieces of mineral rocks (0.5 inch on an average) One pack is enough for a 14 gallon tank and lasts for a good 4-6 months. So it's not at all heavy on your pocket. SUPPLIES ESSENTIAL MINERALS & TRACE ELEMENTS --- A critical constituent of the natural habitat and ecosystem of fish so lacking in captivity, these unique 100% natural rocks are packed with over 60 essential minerals and trace elements, promoting their well-being, fertility and longevity. It is said that it increases egg production and results in fry survival rate. LENDS NATURAL LOOK & FEEL TO AQUARIUM & BOOSTS IMMUNITY --- These slow-releasing, nutrient-rich rocks are effective for up to six months, delivering fish the minerals and trace elements they need to optimize their digestion and bolster their immune systems. PURIFIES & IMPROVES AQUARIUM WATER --- Thanks to their unique stratification and composition which give them natural filtering abilities through ionic exchange, water purifiers help cleanse aquarium water of harmful bacteria, algae fungi, parasites and toxins, ensuring fish a healthier aquatic environment. They also benefit aquarium hydrophytes by converting fish waste into mineral-rich manure.