RBTA- 1-3 inches. This strain is aquarium hardy and needs little to thrive. It responds well to large variety of conditions; hi/lo flow, hi/low light, no feeding necessary. Place the nem so the foot can attach sideways or upside down, and allow the nem to pull into the shade or stretch into full light, and it will stay put. This unaltered pic was taken with an iphone under white light. The nems will fluoresce pink under blue light.