CaribSea LifeRock Nano Reef Kit (2 pieces) – A set of two petite LifeRock formations specifically selected for nano and pico reef tanks. Each piece is hand-crafted with arches, holes, and realistic shapes to maximize coral placement and swim-through spaces in a small aquarium. LifeRock nano pieces come biologically pre-seeded with dormant beneficial bacteria and adorned in natural purple tones of dried coralline algae. This allows even the smallest marine aquariums to quickly achieve a mature, established look and robust biological filtration in a safe, pest-free way.