Glow in the Dark Aquarium and Fish Tank Micro Rubble * 3 Colors * Pebbles (8oz Bag) Make your fish tank come to life when you turn out the lights Completely Safe & Non-Toxic Ideal for: Aquariums, jewelry making, art projects, gardening and more! Each stone is unique in size - generally they will be 5mm-10mm 100% Weather & Water Resistant (works with either fresh or salt water aquariums)