Green Thumb Water Gardens have been helping our Little Rock neighbors create and maintain their beautiful water gardens since 1959. From your first goldfish to the most exotic Japanese Koi, Green Thumb has years of experience helping create the perfect serene environment.. Helix Brand life support equipment. Pond maintenance,Pond cleaning,filter upgrades. Green Water clearing,water quality testing. Pond building and retrofitting. Japanese koi,domestic koi,goldfish,algae eaters.