AquaStik Putty from Two Little Fishes is a non-toxic aquarium putty in easily camouflaged stone grey, and an invaluable tool for aquascaping, coral propagation, modifications and repair. Wet, it has a clay-like consistency and can be kneaded by hand without waste or mess, eliminating the need for any putty tools; it mixes in minutes and hardens in 20, with no strong odors.