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One of the initial wild fish a child is likely to capture in a net in small streams and ponds is the three-spined stickleback, Gasterosteus aculeatus. This species is extremely resilient and will prey on any unsuspecting smaller creatures that pass by.

During this season, the male fish who are ready to breed, measuring up to 8cm (3in), undergo a transformation from silver to red-chested, green-sided, blue-eyed fighters. They construct a nest in shallow water that is high in oxygen, to prepare for their role as a caring and safeguarding father.

The vibrant hues and alluring swimming behavior are employed to attract a female to lay approximately 200 eggs in the nest. Then, the female is driven away while the brightly colored male defends against any potential threats, all while ensuring proper oxygen supply to the developing eggs by fanning them in the nest.

After approximately one week to 10 days, the small newborns are gathered and safeguarded. In some cases, they are carried in the mouth back to the nest if they wander too far.

This fish species is commonly found in Britain and is often the first to repopulate streams that have been contaminated. Sticklebacks are able to survive in both brackish and saltwater. They have the ability to lock their spines, making it challenging for predators to consume them.

Source: theguardian.com