Male stickleback

When does the male stickleback turn red?

The male stickleback's belly turns red at the start of the breeding season in spring. Normally the belly of this small fish is silver-coloured, the rest of it varying from brown to green. But when the time comes for him to mate he becomes very active in attracting females with his bright new colour.

In building the home and rearing the family the male stickleback performs many of the functions usually associated with a female fish. He chooses the place for the nest, collects the stems of various aquatic plants and binds them together using a threadlike web secreted from his kidney.

Once the female has been enticed into his nest, she will lay her eggs and depart, leaving him on guard. He watches over the eggs with great care and even looks after the baby fish.

An unusual feature of sticklebacks is that they have no scales, although some species have bony armour plates. They are related to pipefish and seahorses.
Stickleback species are found in fresh water environments in Europe, Asia and North America. They feed on small crustaceans and fish larvae.
Sticklebacks are distinguished by the presence of strong and clearly isolated spines in the dorsal fin. All species show a similar mating behaviour, which is also unusual among fishes. The males construct a nest from vegetation held together by secretions from their kidneys. The males then attract females to the nest who lay their eggs inside where the male can fertilise them. The male then guards the eggs until they hatch.