Longnose Twig Catfish (Farlowella gracilis) is a popular species of armored catfish originating from the tropical river basins of Colombia. They go by a variety of common names within the aquarium hobby including: Longnose Twig Catfish, Twig Catfish, Whiptail Catfish and Slender Armored Cat. Many hobbyists keeping tropical community aquariums or Amazon biotope aquariums keep Longnose Twig Catfish both for their attractive appearance and their ability to consume algae and detritus.

Longnose Twig Catfish perform an important role within the aquarium ecosystem by keeping excess algae in check and helping to keep the aquarium substrate free of decaying plant material and excess foodstuffs. They are also known for being a long lived and very hardy species once acclimated in the aquarium environment.