Three-spined stickleback was named after its noticeable 3 (rarely 4) erectable spines in front of the dorsal fin. With a few exceptions it can be found in all Europe, Algeria, North Asia as well as North America. It is salt tolerant and populates limnic and coastal water, as well as the zones of brackish water. Like all sticklebacks, the three-spined stickleback also does not have any scales, but bone plates, overlapping each other in a roof-tile manner.

Body length amounts to 11 cm. Their color varies widely and is affected by the preferred habitat. The food of a three-spined stickleback consists in insect larvae, worms, fish spawn and fish youth.

At the spawning time in May/July, those parts of the population living in the coastal water search for the lower reaches of rivers. Males build the nests of fine plant parts and algae over the sandy substrate, where the egg deposition and fertilization occur. Males overtake the protection and fostering of the spawn.

Three-spined stickleback lives only 2 to 3 years. This, rather unsusceptible fish species is not endangered and has no economic significance.