The ten-spined stickleback has eight to ten spines on its back and three on its belly. The fish is the smallest indigenous fish species of the Netherlands and grows to a maximum of 7 centimeters in length. It lives only one or two years and usually dies after reproducing in its second year of life. Spawning season is from April till July. The male builds a nest in thick overgrowth of waterweed and hornwort. Just like the three-spined stickleback, this fish performs an extensive mating ritual and the males care for the young.