Fry / Baitfish

Nothing here is about the adult perch — it's the fry, this year's young, shoaling in open water and along the margins by late summer, that turns a reservoir trout predatory. From August a big overwintered brown or an older rainbow that's spent the summer on buzzer and daphnia switches over almost entirely, and it stops being subtle about it: the takes on a lure fished through a fry shoal are hard, often visible, sometimes violent enough to see from the bank. Look for the fry themselves first — dimpling, scattering, sometimes driven right onto the surface — and fish a Minkie, Cat's Whisker, Appetiser or Floating Fry through and past the commotion rather than into the middle of it. This runs through autumn into November and is, alongside the daddy and the last buzzers, one of the three things actually worth having on a reservoir at that time of year.

• British IslesCommon
• Continental EuropeOccasional
• Atlantic fringeOccasional
• ScandinaviaOccasional
• The AlpsScarce

The European perch (Perca fluviatilis), commonly called the common perch or redfin perch, is a predatory freshwater fish native to Europe and North Asia. It has greenish colouring with distinctive red pelvic, anal and caudal fins, and five to eight dark vertical bars on its sides. It inhabits slow-flowing rivers, deep lakes and ponds throughout most of Europe, avoiding the Iberian Peninsula, with its range extending eastward to Siberia's Kolyma River.