The Day I Picked a Knife Fight With a Lionfish and the Lionfish Won

Benjamin Hadfield   Mar 30, 2026

The Day I Picked a Knife Fight With a Lionfish and the Lionfish Won

There are moments in life when a man is offered a clean, shining choice between wisdom and nonsense.

On this particular day, deep on a trimix deco dive, helium and misplaced confidence teamed up to make sure I chose nonsense.

The dive itself was glorious. Deep reef, easy breathing, clear head, expensive gas doing exactly what expensive gas is supposed to do. My buddy and I were drifting along in that serious, cathedral-like stillness you only get when you are deep enough that every movement feels important and every glance at your computer feels like checking in with an accountant who also controls your future. We were loaded down with the usual technical-diver yard sale: tanks, deco bottles, clips, hoses, lights, computers, backup computers, and enough gear to look like two anxious Christmas trees that had learned gas planning.

Then I saw him.

A lionfish.

Not just any lionfish, either. This was a striped little warlord. Big. Beautiful. Invasive. Completely sure of himself. He hovered there with the swagger of a Marine gunnery sergeant and the fashion sense of a Vegas chandelier. The sort of fish that looks like it should be introduced by a drum roll.

Now, I knew lionfish were venomous. I was not under the impression that they were underwater Labradoodles. I had cleaned enough of them before to know the spines were not decorative. But knowledge and judgment are not always on speaking terms. In that moment, the mature adult in me stepped aside, and my inner twelve-year-old grabbed the controls with both sticky little hands.

The problem was that I did not have proper lionfish-hunting gear. On a trimix dive, I usually skip the spear and keeper because I already have enough equipment hanging off me to qualify as a reef mooring. But I did have a sharp titanium knife, and unfortunately, that was all the encouragement Bad Ideas Incorporated needed.

So I drew it.

Like a complete idiot.

I eased in, gave the fish a poke, and he scooted away.

I poked him again.

At that point, this stopped being “diver helps the ecosystem” and became “grown man loses a duel with a venomous feather duster.”

The fish turned, squared up, and kept those spines facing me with the tactical poise of a tiny underwater drill instructor. I repositioned. He repositioned. I adjusted. He adjusted. The whole thing became a fencing match between one overconfident mammal and one heavily armed aquatic goblin.

Then I found what I was certain was the angle.

You know the angle.

The angle that exists only to lure you into paying tuition to the University of Consequences.

So I committed.

Fast. Hard. Certain.

And Teufels fisch, as I later named him, introduced my hand to his opinion.

He turned with shocking speed and drove his spines into my thumb, hand, and finger so deeply and so efficiently that it felt less like a sting and more like I had been personally cursed by Poseidon in front of witnesses.

Instant pain.

Not ordinary pain.

Not “well, this is unfortunate” pain.

This was bright, electric, roaring, deeply personal pain. The kind that does not arrive politely. The kind that kicks in the front door, throws your furniture out the window, and starts collecting rent.

I managed not to drop the knife, which remains one of the very few heroic details available to me in this entire story. I put it away, because the last thing this situation needed was me turning a venom injury into a slapstick knife-recovery mission. And then I did the most intelligent thing I had done in the previous five minutes:

I decided I wanted out of the water.

There was only one minor complication.

We still had about twenty-five minutes of deco to do.

And deco, unlike feelings, does not care what kind of day you are having.

That was when the real fight began. Not with the fish. With my own brain.

Because pain is greedy, it wants all of your attention. It wants the whole stage. It wants to turn your world into one giant flashing sign that says FIX THIS NOW. And underwater, especially on deco, that is how people graduate from “bad situation” to “obituary with comments.”

So I went to work on the only thing I actually could control: my composure.

Not my comfort. Not my pain. Not my pride. Just my composure.

I made my world very small.

Breathe… Signal… Check depth… Watch my buddy… Launch the bag… Do the switch… Confirm the gas… Breathe again.

That is one of the great tricks for stress underwater: do not try to win the whole war in your head. Win the next ten seconds. Stress management is not about feeling calm. It is about behaving in an organized way while your nervous system is running around the room with a frying pan.

People talk about “staying calm” as if calmness is a personality trait you either brought from home or forgot in the truck. It is not. Calm underwater is mostly a procedure of wearing a fake mustache. When things go wrong, you narrow your world. You stop negotiating with the pain. You stop imagining seventeen future disasters. You shorten your thoughts until they fit inside a checklist.

My thumb, by this point, had resigned from active service. It was still technically present, but only in the administrative sense. Functionally, it had become a screaming ornament. I signaled my buddy to launch the DSMB so the boat would have our location.

Usually, he was fairly quick with that.

On this day, however, it was like watching a man knit a parachute from scratch while contemplating philosophy.

I am sure he was doing his best.

I am also sure that in the middle of a lionfish envenomation, time stretched out like warm taffy, and every second came through customs.

Eventually, the bag was up, and we started toward our first stop. Then came the gas switch, which is already one of those tasks that deserves your respect even when your hand is not trying to detach itself from your body out of principle.

He went through his checks… I went through mine.

Every button push felt like I was trying to operate a computer with a handful of lightning. But again, same method: shrink the moment, obey the sequence, refuse drama. Pain can shout. Procedure gets the vote.

That became the rhythm all the way up. Stop by stop. Task by task. Seventy feet. Sixty. Fifty. Forty. Thirty. Another gas change. Another round of clip, check, confirm, breathe. I did not feel brave. I did not feel cool. I felt like a man trying not to let one thumb turn an orderly ascent into a deeply regrettable life choice.

And that, I think, is worth saying clearly: courage in stressful moments often looks very boring. It does not always roar. Sometimes it just mutters, “Do the next correct thing,” for twenty-five straight minutes while your nervous system files a complaint.

By the time we got shallow, I had paid the deco gods every penny they were owed, plus interest and what felt like an emotional processing fee.

We surfaced within about thirty feet of the boat, which was close enough to be insulting and far enough to be irritating. I remember thinking that if I had not already been thoroughly humbled by a fish with the attitude of a staff NCO, that would have done it.

We made our way over. I still tried to hold onto a little dignity. I waited for my buddy to get sorted first. I waited for my turn. I acted like this was all very manageable and not, in fact, a full-scale mutiny being staged by my hand.

But my crew knew immediately that something was wrong.

I am not the diver who usually asks for help. I take my fins off. I climb the ladder. I get my own gear off. I prefer my suffering neat, private, and mildly inconvenient to everyone else. So when I started handing fins up and needed help getting unclipped, the mood changed instantly.

My DM looked at me with that exact expression dive professionals get when the music changes and they know the story has stopped being funny.

“What’s wrong?”

“I took a lionfish hit.”

She knew.

Everyone knew.

This was not a “walk it off” situation. This was a great amount of Pain in a wetsuit.

“How long ago?”

“About thirty minutes.”

And then the concern level moved from casual to very real.

Now here is where the story turns from funny to useful.

Because lionfish are not just pointy. They are venomous in a very organized and deeply offensive way. Lionfish have venom-bearing spines on the dorsal, pelvic, and anal fins—13 dorsal, 2 pelvic, and 3 anal for a total of 18 venomous spines. The glands sit in grooves along the spines, and when the spine punctures you, venom is introduced into the wound. NOAA describes the venom as a mix of proteins, a neuromuscular toxin, and acetylcholine. The result can be immediate severe pain, swelling, redness or blanching, warmth, blistering, and sometimes nausea, vomiting, weakness, sweating, shortness of breath, or even paralysis-like symptoms in more serious cases. DAN notes that swelling can become severe enough in fingers to threaten circulation and tissue.

The pain is so dramatic because the injury is doing two rude things at once: first, you have been punctured by a spine; second, the venom is now throwing a chemistry tantrum in your tissue. It is not usually lethal in a healthy adult, but “not usually lethal” is a very poor synonym for “pleasant.” Lionfish venom can hurt for hours, sometimes longer, and local swelling can stick around for days. Infection and retained spine fragments are real concerns too, which is why the phrase “I’ll just tough it out” should not be given voting rights in your treatment plan.

And now we come to Mistake Number Two.

Mistake Number One, obviously, was trying to assassinate a lionfish with a knife on a trimix deco dive.

Mistake Number Two was reaching for ice.

What lionfish stings want is hot water, not an arctic cocktail. The standard first-aid move is to rinse the wound, remove any obvious foreign material if it can be done safely, control bleeding, and immerse the affected area in non-scalding hot water, generally about 110–113°F (43.3–45°C), for 30 to 90 minutes, repeating as needed. Heat can provide major pain relief and may help inactivate some venom components. DAN specifically warns that the victim may not judge heat accurately because the pain is so intense, so somebody else should test the water first unless you are aiming to upgrade “lionfish sting” to “lionfish sting plus thermal burn.”

Ice is not the hero at the start. Later, after the hot-water phase, cold packs may be used for swelling, but the immediate go-to is heat. That is the part I got wrong, and the ocean, as always, was delighted to grade my work in real time.

A proper response after that includes pain control, watching closely for worsening swelling or body-wide symptoms, and getting medically evaluated—especially if the punctures are deep, the hand is involved, pain stays severe, fragments may be retained, or symptoms spread beyond the sting site. Medical follow-up may include tetanus review, wound care, stronger pain control, imaging to look for retained spines, and antibiotics if infection or a contaminated puncture becomes a concern. If someone develops weakness, vomiting, faintness, trouble breathing, or altered consciousness, that is not a “let’s keep an eye on it” moment. That is an emergency. In the U.S., Poison Control is available at 1-800-222-1222 for immediate guidance.

I also took an antihistamine, which made sense for one particular reason and not for several others. An antihistamine can help if part of the body’s response is allergic-type—rash, itching, swelling beyond the local injury, or a generalized reaction. It is not an antidote. It does not neutralize lionfish venom. It does not replace hot water, wound care, or medical evaluation. In severe allergic reactions, first aid may escalate to epinephrine and urgent medical care. So yes, antihistamines have a role in the right situation, but no, they are not magic fish-venom erasers.

Hydration matters too, although not because water has any special anti-lionfish powers. It matters because after a deep dive, stress, pain, adrenaline, and a whole lot of physiological grumbling, being dried out is not helping anything. Hydration supports recovery. It does not replace treatment. It just keeps you from becoming a medically interesting raisin on top of everything else. This part is more common-sense support than lionfish-specific medicine, but it is still good practice after the circus has left town.

The funny part—if there is one—is that when I am in my worst pain, I tend to smile and crack jokes. This confuses people, because apparently most folks prefer their agony in a more straightforward format. But humor does something useful in ugly moments: it reminds you that the pain is not the whole story. It keeps one corner of your mind free. It breaks the spell. It says, “Yes, this is awful, but I am still here, and I still get to decide what kind of fool I’m going to be about it.”

That matters underwater, and frankly it matters in life.

Because stress management is not just for diving accidents. It is for arguments, funerals, bad news, blown engines, ugly diagnoses, business disasters, and every other moment when panic makes a convincing sales pitch. The lesson is almost always the same: make the world smaller, not bigger. Do the next correct thing. Do not let pain, fear, embarrassment, or ego run the room. Those things are loud, but they are not wise.

And there is another lesson too, one I dislike because it is annoyingly mature:

Preparedness is an act of compassion.

For yourself.

For your buddy.

For your crew.

For the people who are going to have to deal with whatever flavor of nonsense you create.

Heat packs on the boat. Good first-aid supplies. A plan. Proper tools for the job. A brain willing to say, “Not today, Junior,” when your inner twelve-year-old starts trying to lead tactical operations.

All of that matters.

Because the ocean is beautiful, but it is not sentimental. It does not grade on effort. It does not care how experienced you are, how expensive your gear is, or how funny you are while being stupid. The sea will let you borrow wonder all day long, but if you get careless, it will invoice you in a currency that hurts.

Teufelsfisch taught me that.

He did not ambush me.

He did not betray me.

He did what lionfish do.

I, on the other hand, briefly looked at a venomous fish on a deep technical dive and thought, “Yes, a knife fight seems reasonable.”

So if anyone in this story deserves the title of clown prince of poor decision-making, it is not the fish.

It is me.

And yet, as much as I hate to admit it, there was a gift in the whole miserable episode.

Pain clarifies.

It strips away vanity.

It exposes habits.

It shows you whether you really trust your training or whether you just like owning equipment with cool clips.

And if you are lucky, it leaves you a little wiser, a little humbler, and slightly less likely to duel sea creatures with cutlery.

Lessons I paid for with my hand

Never bring a knife to a lionfish fight when what you actually need is better judgment.

When stress hits, shrink your world to the next correct action.

Panic is loud, but procedure gets you home.

Humor is not denial if it helps you stay functional.

The right gear and a real first-aid kit are not optional decorations.

Hot water belongs in the treatment plan. Ice belongs in your drink.

Your inner twelve-year-old should not be allowed to make operational decisions at depth.

And finally: dignity is nice, but composure is better. Pride wants to look tough. Wisdom wants to get everyone home safely.