Hook size confuses a lot of newer UK anglers because the numbering system is counterintuitive – and then changes direction entirely once you move into bigger hook sizes. This guide clears up the sizing system and gives practical size recommendations by species.
How Hook Sizing Works
Standard hook sizes run from very small numbers upward, but counterintuitively, a bigger number means a smaller hook: a size 20 hook is tiny (suited to a single maggot), while a size 6 hook is comparatively large. Once hooks get big enough, sizing switches to an “aught” system (1/0, 2/0, 3/0 and upward) where the numbering flips – a bigger number now means a bigger hook. A 2/0 hook is bigger than a 1/0, which is itself bigger than a size 1.
Hook Sizes by Species
Roach, rudd, small skimmers: size 16-20, matched to single maggot, small pinch of bread, or a single grain of corn.
Bream, tench, general coarse: size 12-16, matched to double maggot, bread flake, or a single boilie/pellet hookbait.
Chub, barbel: size 8-12, matched to larger bread flake, luncheon meat cubes, or pellet hookbaits, with barbel sometimes needing a stronger-gauge hook for their power even at moderate sizes.
Carp: size 6-10 for most method feeder and boilie fishing, occasionally down to size 4 for bigger single hookbaits or up to size 12 for smaller pellet/corn presentations on pressured waters.
Pike: size 4 to 2/0, usually as trebles for deadbaiting or single hooks for larger lures, always fished on wire trace regardless of hook size due to pike’s teeth.
Zander and perch: size 4-8 for bait fishing (zander deadbaiting, perch on worm), or appropriately sized trebles/single hooks matched to lure size for lure fishing.
Sea fishing (bass, cod, general bottom fishing): size 1 to 6/0 depending on target species and bait size, with bigger baits like whole mackerel needing hooks up toward 4/0-6/0 and smaller bait presentations for whiting or flounder sitting around size 1-4.
Barbless vs Barbed
Many UK fisheries require barbless (or micro-barbed) hooks to reduce injury and speed up unhooking – check the specific water’s rules. Barbless hooks are also simply easier and quicker to remove even where not mandated, and cause less damage on a missed strike.
Matching Hook to Bait, Not Just Species
The bait size matters as much as the target species when choosing a hook – a size 16 hook suits a single maggot regardless of whether you are after roach or a smaller bonus fish, while a size 8 suits a bigger piece of bread or meat regardless of the specific species you expect to catch. See our full fishing hooks guide for pattern types (eyed, spade-end, wide-gape, and more) alongside sizing.