April is an important month in the calendar for many fish, so also for anglers and hydrotechers. It is then that the spring spawning of many predators of our fresh waters ends, from small steelhead through medium grayling, rainbow trout and perch to large pike. It also begins the reproduction of a multitude of still-living species from the most diverse families – from cyprinids to piscivores and sticklebacks to sticklebacks.