These amazing natural rocks have bizarre mesmerising shapes which will create a stunning aquascape the rocks have little craters cracks and gaps and are reminiscent of volcanic rock they are sandblasted which removes approx 1 mm of the surface while gently rounding the sharp edges and corners these decorative rocks provide a safe place for your fish to hide away they will enjoy swimming through the larger holes and hollows the rocks have a high calcium content and are ideal for aquarium