Fish
Ninespine Stickleback
Pungitius pungitius · also called ninespine sticklebacks, nine-spined stickleback
Count the dorsal spines on a ninespine stickleback and the total might come out to eight, ten, or eleven just as easily as nine, a small naming inconsistency in a fish whose male parents put in more nest-building effort than most fish ever attempt.
Overview
The ninespine stickleback, Pungitius pungitius, is a small, cold-water fish with one of the broadest natural distributions of any freshwater or coastal fish, found across North America, Europe, and Asia. Its inconsistent spine count, dedicated male parental care, and remarkable circumpolar range make it one of the more ecologically successful small fish of the Northern Hemisphere.
A name that doesn’t quite add up
Few common names invite as much good-natured skepticism as the ninespine stickleback’s, since a quick spine count on any given individual is just as likely to land on seven, ten, or twelve as it is on the number the name promises.
Status
Least Concern — widespread and abundant across suitable cold-water habitat throughout its enormous circumpolar range.
Ninespine Stickleback: common questions
Why doesn't the ninespine stickleback always have nine spines?
Despite its name, individual ninespine sticklebacks commonly show anywhere from seven to twelve dorsal spines, meaning the actual spine count frequently does not match the number implied by the common name, a naming quirk that can confuse anyone counting spines to confirm identification.
Do ninespine stickleback parents take care of their young?
Yes, a male ninespine stickleback builds a nest from plant material and actively defends both the eggs and the newly hatched fry within it, a level of dedicated paternal care that is genuinely unusual among fish, most of which provide no parental care at all.
How does the ninespine stickleback compare to the three-spined stickleback?
The ninespine stickleback is typically smaller than its close relative the three-spined stickleback, and while both tolerate a range of water conditions, the ninespine stickleback carries considerably more dorsal spines on average, despite the inconsistency between its name and actual spine count.
Can the ninespine stickleback live in salt water?
It tolerates brackish coastal water reasonably well alongside fresh water, a flexibility that lets it move between river, lake, and coastal wetland habitat and helps explain why the species has such an unusually broad natural range across the Northern Hemisphere.