How to Choose Fishing Hook Size (2026 Guide)
Hook size in Ireland depends on the fish you're after, the bait size and where you're fishing – not one universal chart. For trout and perch, size 10-14 covers most rivers and loughs; for pike and other predators, size 2 down to 6/0 handles bigger baits and bigger mouths; for pier and beach work, size 2-6 suits mackerel strip and lugworm.
The hidden catch: hook numbering runs backwards on one scale and forwards on another, so a size 14 is smaller than a size 8, but a 1/0 is bigger than a size 1. Get that wrong and you'll buy the opposite of what you need.
How do you choose the right fishing hook size?
- Trout and perch on Irish rivers: size 10-14 hooks match natural food size.
- Pike and predator fishing: size 2 to 6/0 hooks hold deadbait and lures securely.
- Pier, beach and boat fishing: size 2-6 hooks suit mackerel strip and lugworm.
- Coarse fishing for bream, tench and carp: size 6-12 depending on bait and venue.
- Two scales exist – smaller numbers mean bigger hooks once you cross into the /0 (aught) range.
Here's the direct answer for anyone standing at a tackle wall in 2026 trying to decide between a packet of size 8s and a packet of 1/0s: match hook size to bait size first, mouth size second. A size 14 nymph hook carries a tiny fly for wild brown trout. A 4/0 or 6/0 treble carries a whole mackerel deadbait for pike. Everything in between scales with what's on the hook.
Why this matters
Get hook size wrong in either direction and you lose fish, not just time. Too small a hook on a big bait and the point never clears the flesh to set. Too large a hook on delicate bait and you tear it apart on the cast or the fish feels the metal and drops it. Irish waters add their own pressure: heavily-fished loughs and rivers see pressured, hook-shy fish, and undersized or oversized gear shows up fast in your hook-up rate.
The scale itself trips people up more than species selection does. Hooks are numbered on two separate systems that run in opposite directions.
| Scale | Direction | Example |
|---|---|---|
| Standard sizes | Bigger number = smaller hook | Size 20 is tiny, size 2 is much larger |
| Aught sizes (/0) | Bigger number = bigger hook | 1/0 is small, 10/0 is huge |
Once you know which scale you're reading, matching hook to species and bait gets straightforward. The fishing rod buyer's guide covers the other half of that equation – rod and hook need to work together, especially on lighter tackle where a hook too heavy for the rod's tip action kills your presentation.
Trout and perch: size 10-14 hooks
Wild brown trout and perch on Irish rivers and loughs feed on small naturals – nymphs, hatching flies, tiny fry. Size 10 to 14 hooks match that scale without spooking fish in clear water. Go smaller, down to size 16 or 18, for low, clear summer conditions on rivers like the Suir or Nore where trout get fussy.
Verdict: size 10-14 is the working range for most Irish trout and perch sessions – buy.
Pike and predator fishing: size 2 to 6/0 hooks
Pike take big baits and big trebles. Deadbaiting a whole mackerel or herring calls for size 4 to 6/0 trebles rigged in pairs, front and rear, so the hook points sit where the take happens. Lure fishing scales down slightly – size 2 to 2/0 depending on lure size and the strength of the wire trace behind it.
This is where using the wrong scale costs you fish. A size 6 treble (small, standard scale) looks similar in a drawer to a 6/0 (huge, aught scale) but they're worlds apart in gape and wire thickness. Check the packet twice before rigging up for a pike session.
Verdict: size 4 to 6/0 for deadbait, size 2 to 2/0 for lures – buy the pair that matches your bait, not just "a treble".
Pier, beach and boat fishing: size 2-6 hooks
Sea fishing off Irish piers and beaches usually means mackerel strip, lugworm or ragworm on size 2 to 6 hooks. Bigger baits for ray or bass push toward size 2 or 1/0; smaller baits for whiting or dogfish sit closer to size 6 or 8. The predator fishing gear guide for pike and zander covers the crossover tackle if you're mixing sea and freshwater predator sessions in the same season.
Verdict: size 2-6 covers most Irish shore sessions – buy a mixed pack and adjust to bait size on the day.
Coarse fishing: size 6-12 hooks
Bream, tench, roach and carp on Irish stillwaters and canals respond to size 6 to 12 hooks depending on bait. Boilies and pellet feeder rigs sit at size 6-10; maggot and caster on the pole or waggler drop to size 12-16. Matching hook to bait size here is about presentation as much as hook-up rate – a hook too big kills the natural fall of a single maggot.
Verdict: size 6-12 for most coarse sessions, scaling down for finer baits – hold your current stock if it already fits this range.
Why hook size varies
Hook choice isn't one number – it moves with several factors at once:
- Bait size – a whole mackerel needs a bigger hook than a single maggot, full stop
- Target species mouth size – trout and perch take small hooks cleanly; pike need gape wide enough to set past bony jaws
- Line and rig strength – heavier line pairs with heavier-wire hooks or the hook straightens under pressure
- Water clarity – clear Irish rivers in summer call for smaller, less visible hooks
- Fishing method – float fishing, feeder fishing and deadbaiting each favour different hook patterns and gapes
- Local rules and best practice – barbless hooks are standard on many catch-and-release fisheries around Ireland
The fishing weights guide for your rig walks through the other side of rig balance – weight and hook size need to work together or the bait won't present naturally.
Related questions
What hook size is best for pike in Ireland?
Size 4 to 6/0 trebles cover deadbaiting for pike in Ireland, with 6/0 reserved for the biggest baits on lakes known for double-figure fish. Lure anglers typically run size 2 to 2/0 single or treble hooks depending on lure weight.
Is a size 6 hook bigger than a size 10?
Size 6 is bigger than size 10 on the standard hook scale, where the number falls as the hook grows. That's the opposite of the aught (/0) scale, where a 10/0 is far bigger than a 1/0.
What hook size for trout fishing in Ireland?
Size 10-14 hooks are standard for wild brown trout across Irish rivers and loughs, dropping to size 16-18 for fussy fish in low, clear summer water. The full fishing rods guide by species pairs rod action with hook and line choice for trout, pike and coarse species.
Most of this comes down to habit once you've fished a stretch of water a few times – you'll know within a season what size works on your local river or lough. Keep a mixed range in the tackle box rather than one packet, because bait size on the day matters more than any fixed rule.
FAQ
How do I choose fishing hook size for beginners?
Start with size 8-10 hooks for general float and feeder fishing, then adjust up for bigger bait or predator species and down for delicate baits like maggot. Most beginner rod and reel combos in Ireland come pre-matched to mid-range line, which pairs well with this hook range.
What is the biggest fishing hook size?
The biggest hooks run up to 20/0 on the aught scale, used mainly in big-game and shark fishing rather than typical Irish freshwater or shore sessions. Pike deadbaiting in Ireland rarely goes past 6/0 to 8/0.
What is the smallest fishing hook size?
Size 32 is the smallest hook on the standard scale, used for tiny midge patterns in fly fishing. Most Irish trout fishing sits between size 10 and 18, well above that extreme.
Do I need barbless hooks in Ireland?
Many Irish stillwaters and catch-and-release fisheries require barbless hooks, so check local rules before you rig up. Barbless hooks also come out faster, which matters on high-volume sessions.
What hook size is best for perch?
Size 8-12 hooks suit perch fishing in Ireland, matched to lobworm, small lures or maggot depending on the venue. Perch have wide mouths for their size, so you can size up slightly compared to trout.
Is a size 2 hook big or small?
A size 2 hook is on the larger end of the standard scale, suited to bigger baits like whole mackerel strip or large lures. It sits below the aught scale, where 1/0 and up take over for the biggest rigs.
What hook size for sea fishing off Irish piers?
Size 2-6 hooks cover most pier and beach fishing in Ireland, scaled to mackerel strip, lugworm or ragworm. Bigger baits for ray push toward size 1/0.
Can one hook size work for every fish?
No single hook size works across species – bait size and target fish mouth size change too much between trout, pike and sea species. Carrying a mixed range from size 14 up to 4/0 covers most Irish sessions.
One last thing
The detail most anglers miss isn't the size number at all – it's wire gauge. Two hooks can share the same size marking and still behave completely differently: a fine-wire size 6 for delicate float work will straighten instantly on a hard-fighting pike, while a heavy-wire size 6 kills the natural fall of a light coarse bait. Read the wire spec on the packet, not just the size, before you rig up for 2026.