RED ALERT

As the waters of ponds, dykes and streams warm up, male sticklebacks come into full breeding mode. Their belly flushes crimson, contrasting nicely with powder-blue eyes, and they become highly aggressive. Pumped-up males chase away not just rivals but also other fish and aquatic creatures, especially if they appear red. Sticklebacks seldom get much attention – apart a brief spell in the limelight during 2015’s Springwatch, when ‘Spineless Si’ became an unlikely TV star – yet these tenacious tiddlers are some of our most charismatic fish.

FIND OUT MORE Learn more about UK fresh waters at www.freshwaterhabitats.org.uk