It’s likely the first fish that many of us saw or caught in the wild, and while it has its challenges, the three-spined stickleback is a delight to keep.
WORDS: NATHAN HILL
WHAT A FABULOUS bundle of genetic confusion the sticklebacks are. As a family, they are somewhat diverse, with at least 16 species across five genera. Of those, one in particular will be familiar to UK aquarists: the threespined stickleback,
Gasterosteus aculeatus, or ‘tiddler’ to the British angler.
Genetic variation within three-spined sticklebacks is profuse. There are the anadromous versions that live in the sea and return to freshwater to spawn, large (up to 11cm) and silvery fish with protective scutes along their flanks—a testament to the different predation pressures they face from their freshwater kin. But we needn’t concern ourselves with those, as they are rarely (if ever) offered to hobbyists.
The freshwater three-spines are all descendants of ancient marine sticklebacks. Denied access back to the sea from some inland encroachment at the fall of the last Ice Age, they settled down into a landlocked lifestyle. They became smaller—adult sizes barely reach 5cm—and lost their armour, instead relying on camouflage and hiding to stay off of the menus of birds. These are the fish that seasonally, suddenly, and scarcely appear in aquarium stores. And what a treat they can be to keep.
An English garden
Sticklebacks have become a staple of many a nature pool, but provided that a few key requirements can be met they can make superb aquarium residents too.
The two factors that will determine success or failure are simple: temperature and oxygen, which go hand in hand. In the wild, these fish are found between 4°C and 20°C pending season, though researchers have pegged them with a higher tolerance of up to 28°C. Aquarists who have kept them will attest that this kind of warmth will rapidly see them off, however.
In the tank setting, a temperature ceiling of 18°C should be the uppermost goal, making sticklebacks the sort of fish that work well in an unheated room, especially over winter. Oxygen can be dealt with by adding an airstone or two to the tank, or simply orienting the filter (or filter outlet) in such a way that it breaks the water’s surface, increasing the surface area and allowing for plenty of gaseous exchange. Just note that no amount of oxygen supplementation will be able to offset excess temperatures if things get too balmy.
Even though they aren’t large fish, three-spines are gregarious and need to be kept in groups, so don’t
