A fish spike (also called a tuna spike, brain spike or ike jime spike) has one job: kill a fish instantly by piercing its brain. It sounds simple, and it is, but a bad spike shows itself fast. It bends on a thick skull, slips in a wet hand, or rusts after one season.
This buying guide covers what actually matters when you spike fish: the steel, the size, the handle and the extras, plus what you should expect to pay.
Quick answer: what to look for in a fish spike
- Solid, stiff stainless steel, ideally 316, which resists rust in salt water.
- The right diameter and length for the fish you catch (see the size table below).
- A handle that grips when wet: cord wraps, texture or a shaped grip.
- A sheath or point cover so it can live in a tackle bag safely.
- Solid construction where the spike meets the handle. It should never wiggle.
What is a fish spike used for?
You use a fish spike right after landing a fish you plan to keep. One push into the brain kills it in about a second. That stops the fish from thrashing, keeps the meat from bruising and building up lactic acid, and leaves the heart beating long enough to bleed the fish well. It's the first step of the Japanese ike jime method, and it's one of the most humane ways to kill a fish.
1. Steel: stiffness and corrosion resistance
The spike has to go through a skull without bending, then survive salt, blood and washdowns. That's why solid stainless steel is the standard:
- 316 stainless is a marine-grade steel with excellent corrosion resistance. It's what we use.
- Avoid thin or hollow spikes for big fish. They flex on tuna skulls. (Hollow spikes do have a use: feeding a shinkei jime wire.)
- Avoid plain steel or cheap plating. It rusts fast in salt water.
2. Size: diameter and length
This is where most people go wrong. A spike that's too small for the fish can skate off the skull or stop short of the brain.
| Spike size | Best for |
|---|---|
| 1/4" diameter × 4" long | Yellowtail, bonito, dorado, rockfish, snapper, school-size tuna |
| 5/16" diameter × 4.5" long | Yellowfin and bluefin. The all-around size if you're unsure. |
| 3/8" diameter × 5" long | Big tuna and other large, thick-skulled fish |
If you fish for a mix of species, size for the biggest fish you regularly keep. A slightly bigger spike still works on smaller fish; a too-small spike doesn't work on big ones.
3. Handle: grip, shape and length
- Grip when wet. Blood and slime make smooth plastic or polished wood slippery. Cord wraps and textured handles hold much better.
- Shape. A straight handle is easy to aim and to store. A T-handle lets you push with your palm but takes more room.
- Length. Enough handle to keep your hand clear of the fish, but short enough to use in a crowded cockpit.
Our spikes use cord-wrapped Calcutta bamboo handles, which grip well wet and float if they go overboard.
4. Extras that matter
- Sheath: protects the point and your hands. Ours has an optional screw-on bamboo sheath.
- Lanyard hole: handy for clipping to a belt or bag.
- Matching gear: if you care how your deck looks, a spike that matches your gaff and deck brush is a nice touch.
How much does a fish spike cost?
- Under $25: basic spikes, often short with plastic handles. Fine for small fish.
- $25–$75: sturdier spikes and many ike jime kits that include shinkei jime wires.
- $75 and up: heavier-duty and handmade spikes built for tuna and years of use. Ours run $94.99–$164.99.
Thinking about a kit with wires? See ike jime tools: what you actually need.
How to use a fish spike
- Control the fish. A wet towel over the eyes calms it.
- Find the brain: above and slightly behind the eye, or the soft spot on top of a tuna's head.
- Push the spike in firmly with a small wiggle. The fish should shudder and go limp.
- Bleed it right away and get it into an ice slurry. See how to bleed a fish.
FAQ
What's the difference between a fish spike, tuna spike and brain spike?
Nothing. They're all names for the same tool, also called an ike jime spike.
What size fish spike do I need?
1/4" for yellowtail, dorado and smaller fish; 5/16" for yellowfin and bluefin; 3/8" for big tuna.
Can I just use a screwdriver?
It's not a good idea. It can bend or slip, and a missed spike hurts the fish without killing it.
Can I get a custom fish spike?
Yes. Choose your colors and size with the Custom Tuna Spike Builder.
