Sticklebacks are found throughout the temperate regions of the Northern Hemisphere, mainly in freshwater. Their breeding habits are fascinating — so much so, in fact, that they are credited with inspiring the development of the aquarium hobby in Europe in the 1700s. The males construct tiny nests consisting of plant material held together by secretions from the kidneys. Males then display for the females, who lay their eggs within the nests. The expectant father then guards the nest from any and all intruders, exhibiting aggression far out of proportion to his size.

The fifteen spined stickleback is one of the few marine dwelling members of the family. Native to the northeastern Atlantic Ocean, it attains a length of 8 inches and is quite hardy in the aquarium. This curious fish does, however, prefer live food in the form of brine shrimp and tiny worms. Sticklebacks in general seem to require quite a bit of food and will lose condition rapidly if not fed adequately. Although quite territorial, small groups can be maintained in aquariums, if enough nest sites are available. Be sure to provide widely spaced groups of sticks and plants so that nesting pairs may have the privacy they require. Watching them go through their reproductive behavior and display to each other is a treat rarely afforded those who study marine fish.

Carefully consider tank mates to keep with sticklebacks. On the one hand, they are live-food specialists, and fairly slow feeders will be out competed by larger fish. On the other, they are quite aggressive and prone to “fin nipping” less agile neighbors. They get along quite well with spider crabs, pipefish, and seahorses.