see text The sticklebacks are a family of ray-finned fishes, the Gasterosteidae which have a Holarctic distribution in fresh, brackish and marine waters.

More recent phylogenetic work has shown that the Gaterosteoidei is more closely related to the Zoarcoidei and the Cottoidei, which means that this taxon would belong in the order Scorpaeniformes.

[2] but in other phylogenetic classifications it is treated as the infraorder Gasterosteales within the suborder Cottoidei or as a sister clade to the Zoarcales in the order Zoarciformes.

The freshwater taxa were trapped in Europe, Asia, and North America after the Ice Age 10,000–20,000 years ago, and have evolved features different from those of the marine species.

[5] Research has shown that Sticklebacks display distinct personality traits, specifically in the area of taking a risk, and, can be considered bold or shy.

Freshwater males develop a red colouration, and although this may be seen in oceanic and benthic species these tend to remain dull-coloured.

Females signal their readiness to mate with solitary rather than shoaling behaviour, a head-up posture; their bellies are also obviously distended with eggs.

[20] Therefore, female sticklebacks may risk fertility and the viability of their offspring by choosing redder, but more deteriorated partners with reduced sperm quality.

The benefits of this is also due to larger eggs and thus offspring survival and fitness[23] Female three-spined sticklebacks adjust their courting behaviour to the risk of inbreeding.

[24] Niko Tinbergen's studies of the behaviour of this fish were important in the early development of ethology as an example of a fixed action pattern.

[27] The adaptations seen in oceanic threespine sticklebacks make them an ideal organism for the study of parallel evolution.

[28] There is a sculpture in Kronstadt dedicated to stickleback, which saved thousands of city residents from starvation during the Leningrad Siege of World War II.