Coldwater Marine Aquatics recommends you keep these animals in 55F-60F water.
The threespine stickleback is the only one of the three subspecies of Gasterosteus aculeatus that is marine, scaleless, and fully plated. Fish in this species are anadramous, living in the ocean but entering brackish water or ascending freshwater streams to spawn. The male threespine stickleback not only builds the nest, he also guards it, takes care of the eggs, and protects the newly hatched larvae.
The maximum length of this saltwater subspecies is 11 cm (4.3 in).
Voracious omnivores, threespine sticklebacks eat small crustaceans, worms, copepods, larvae of adult aquatic insects, small fishes, and occasionally their own eggs and fry.