Sticklebacks have not captivated aquarists since the days when children went pond dipping to stock their aquariums. However Germans have lately imported an oriental species, Pungitius sinensis, the Amur or Chinese nine-spined stickleback. P. sinensis are small fish, growing usually to 6.5 centimeters or under 2 and a 1/2 inches, and sometimes 9 centimeters, or nearly 4 inches in length; reportedly, in favorable Korean environments, they reach 15 centimeters, or 6 inches long. This species is eastern Palearctic in its distribution, being native from Siberian locations like Kamchatka and the Amur basin, southwards to northern China, and is also present on nearby islands such as those of Japan.
Sticklebacks have long confused ichthyologists, enlightened ethologists, and amused children. Historically they were assumed to be related to the seahorses and other pipefishes, although this systematic position is now disfavored; instead they are thought to be related to the sculpins and eelpouts. Their namesake spines are, in fact, robust fin rays, which are the defence of these curious fishes. Sticklebacks are well studied for their complex behaviors, and this includes their nest building activities for the purpose of parental care. These are psychologically complex fishes, in a way that is easy to study, and should encourage us to respect fishes as we do other animals.
All the sticklebacks are native to the temperate zone, and therefore none of them can be considered as suitable fishes for tropical aquariums. An aquarium housing any P. sinensis should not become too warm, and ideally it seems the water temperature should not exceed 18 degrees centigrade. (Perhaps this species is one of those, that would well benefit from a chiller?) The entire stickleback clade are also considered to be carnivorous, consuming tiny arthropods and other small prey. In the aquarium defrosted items will be accepted, if they are of a suitable nature for microcarnivores. Upon hatching, the baby sticklebacks are known to begin subsisting on biofilms, from leaving their nest until graduating into carnivory.
P. sinensis is associated primarily with clean and well oxygenated freshwaters, although adult fish are able to survive even in marine environments However when this species is in saltwater environments, it's ability to build nests using a sticky secretion as a natural glue, appears to be curiously impaired; furthermore the offspring cannot survive a low salinity of 8 ppt. This is essentially a freshwater stickleback, one that seemingly fares best in downstream pools, thickly grown with plenty aquatic plants.
Natural nest building, which is performed only by the male fish, will obviously require suitable aquatic vegetation; it is the male stickleback that builds and guards his nest. Members of the genus Pungitius may be housed together with similarly sized fish, with similar environmental requirements, however their compatibility and broader captive care is not so well documented, as are those of the three- and fifteen-spined sticklebacks, which belong to allied genera. Incidentally sticklebacks are so individually variable, that the genera are difficult to demarcate using what seem to be obvious traits, like the number of dorsal spines they happen to possess - despite our habit of naming species by a number of spines.
Not much is written about the care of sticklebacks other than the three-spined species. The latter has a reputation as a fin nipper, with the males being more aggressive than the females; yet this is subject to individual personality, and wether the fish are in nesting mood. I have never witnessed aggression among the marine, fifteen-spined sticklebacks, but then again, I have never seen them nesting in a community tank: at other times, they were docile and unaggressive,at least towards pipefishes.
