Baku, April 2, AZERTAC Three-spined stickleback never lived in the Caspian Sea; for the first time was found in 1984. This is a tiny fish 5 to 10 cm. The stickleback feeds on benthic organisms, tiny crustaceans, insect larvae, worms, fish eggs and fry. The life of three-spined stickleback is 3-4 years.