Stickleback - Gasterosteus aculeatus and Pungitius pungitius

Many of us remember the stickleback from our childhood days and probably did not realise back then how small this species of fish really is. It is one of the smallest British freshwater coarse fish and also one of the most interesting.

There are numerous types of stickleback, with the three-spined being the most common and widespread. The nine-spined stickleback is found in as many locations across the UK, yet in much smaller numbers.

Stickleback Identification

Three-spined Stickleback (Gasterosteus aculeatus) Identification

The stickleback is really a very impressive and distinctive fish. The three-spined stickleback does not grow very big or long yet it has a number of characteristics that make it stand out.

Along its back, this fish has three very sharp spines; hence its name "three-spined stickleback". The first two spines are longer than the third and these are featured halfway along the back just before a second dorsal fin.

The stickleback also has very large pectoral fins, which he not only uses for steering and movement but also to fan and provide oxygen for the stickleback eggs just after they have been laid.

In place of the pelvic fin there is a long spine.

The colour of this fish depends on location and its habitat. It can vary from anything between an olive green - brown to a greyish blue with silvery flanks. The underside of the fish is silver and the fins are pale. The caudal fin is small with a thin wrist.

During the spawning period the male stickleback develops a red throat and his eyes turn electric blue.

Nine-spined Stickleback (Pungitius pungitius) Identification

The nine-spined stickleback is much the same as the three-spined fish yet possesses between eight and ten small spines down the length of its back. These low spines are not as long as on the three-spined stickleback but this doesn't mean to say that they are not just as sharp!

The nine-spined stickleback is smaller and more slender than its lesser-spined cousin and it is not as colourful during the breeding period.

Stickleback Habitat

The stickleback is widespread across western Europe and Britain. The nine-spined stickleback is not found in Scotland or in the south-west of England or Wales but is common in all other parts of the UK. The three-spined stickleback can be located in all areas of England, Wales, Ireland and some parts of Scotland.

This species of fish is extremely hardy and tolerant of most types of water, even the most polluted. It can be found living in lakes, slow-moderate flowing rivers, ponds, canals, ditches, estuaries and even the sea. It is not a good swimmer and therefore avoids fast waters.

In shallow water the stickleback stays close to the bottom and where there is more depth is remains close to the vegetation.

Natural Stickleback Food

Both types of stickleback have the same type of diet, which is fairly varied.

The feed on small crustaceans, molluscs, worms, nymphs, insect larvae and the eggs and small fry of other species of fish, which is known to cause some devastation to certain species.

Stickleback Reproduction

The way in which stickleback reproduce is truly fascinating and unique. Between the months of May and July, depending on location, the male stickleback starts to build a nest out of nearby vegetation including plants, weeds and bits of grass. The nest is about the size of an apricot and is glued together with mucous threads that he produces.

By this time, he has transformed his dull appearance into one of brilliant colour and attraction in the hope of luring one or more females to his nest.

The female enters the nest and deposits a very small number of between 100 - 150 eggs in the middle of the breeding home, after which the male goes in to fertilise them.

After this the male stays by the nest, guarding it from predators and other males, until the eggs hatch, which takes about 7 - 10 days. Ever the doting father, he stays with the small fry until they are able to fend for themselves and make their own way about.

A great number of male stickleback die from exhaustion after spawning as do lesser numbers of females from the stress.

The Stickleback's Vital Statistics

  • Average weight: 1/10 oz (3g)
  • Average length: 2 inches (5cm)
  • Life-span: 3 to 4 years
  • Current UK record: 4 grammes (Cambridgeshire lake)

Share on your social networks

© Copyright 2023