If you are going to eat an animal, the question is not whether its death is sad. It is how much suffering your choice actually adds to the world for each gram of protein you get back. Most people answer with a feeling instead, and the feeling favors the cow, because a cow is one large familiar death and a tin of sardines looks like a small massacre. Scored properly, the feeling is backwards.
How to score it
One thing decides this: the suffering your demand actually adds, per gram of protein. That is not the same as the raw number of animals that die. It breaks into a few separate questions.
How many animals die for the protein you get?
How much can each one actually suffer?
How much life does each death cut short?
What does the food cost everything else that is alive?
And underneath all of it: how much of that would have happened anyway, without you?
That last question matters more than people expect, and it is where the cow and the sardine part ways.
The case for beef
Beef's case is stronger than most people who eat fish want to admit, and it starts with size.
Cows are enormous. A meat eater gets through roughly eleven cattle in a lifetime and well over two thousand chickens, almost entirely because a chicken is small and a steer is not. Fewer animals die per calorie from beef than from nearly any other meat.
Per death, beef is mild. Weight each death by how much the animal can plausibly suffer and the result is stark: beef and dairy come out something like hundreds to a thousand times less harmful per kilogram than chicken or eggs.
A pastured steer can have a real life. It grazes, moves with a herd it recognizes, and reaches a regulated death after most of a normal life. That is more than almost any farmed animal gets.
One animal, two foods. The same cow yields milk, so its existence is not spent on meat alone.
If your rule is to kill the fewest animals and hurt each one least, beef is a serious answer, and the chicken next to it is where the real cruelty is.
The case for the sardine
The sardine has to overcome that body count. A single steer carries the protein of many thousands of sardines, so on raw numbers it loses, and badly. It wins anyway, on four fronts.
It barely suffers
Sardines and anchovies are about as simple as a vertebrate gets.
They are broadcast spawners, releasing eggs into open water with no pair bonding and no parental care.
They are filter feeders, with no complex hunting and limited learning or navigation.
Their nervous systems are small.
On a scale where a human's capacity to suffer is one, the most careful attempts to score a sardine land near 0.045, far below a cow and a fraction of almost anything else we farm. So the thousands-to-one body count is not multiplied against an equal. Each sardine death carries only a small slice of the moral weight inside the cow, and the gap closes fast once you stop counting bodies and start counting the capacity to feel within them.
Its death is mostly not your doing
This is the part that actually decides it. A beef cow is brought into existence, raised, and killed entirely on your account; none of it happens without the demand. A wild sardine is not farmed. It already exists, and it was already going to die, almost certainly badly.
Sardines lay tens to hundreds of thousands of eggs, and fewer than one in a thousand reach adulthood.
The ones that do mostly die by predation: chased to exhaustion, then swallowed alive and suffocating or dissolving in a stomach for something like twenty minutes.
The rest go slower, by starvation or disease.
Set against that, a net closes around a shoal at night, when the fish are calm, and hauls them out over an hour or two, where they die from the crush of the catch or from falling oxygen. It is genuinely uncertain which death is worse, and the people who have looked hardest at it have grown less sure over time, not more. That uncertainty is the whole point. For the cow, the entire life and death are added to the world. For the sardine, your demand mostly swaps one hard death for another. The catch is capped by quota on top of that, so eating the fish largely redirects it away from fishmeal and pet food rather than pulling more out of the sea.
It costs the rest of the world almost nothing
Everything that is not the animal also counts, and here the gap is enormous.
Sardines need no land, no fresh water, and no feed; they sit at the bottom of the food chain and rank among the lowest-footprint protein of any kind.
Beef sits at the opposite extreme on land, water, and greenhouse gas per gram of protein.
The land beef takes is the single biggest driver of habitat loss, which kills far more wild animals than any fishery does.
And the clean-hands alternative is not as clean as it looks. Plant farming kills field animals by the tractor-load: mice, nesting birds, and countless insects die to bring in a crop. A plate of plants is not bloodless, and most of the crop grown on Earth goes to feed livestock anyway.
It feeds you better, for less
A sardine also fixes the problem that makes people give up on eating well in the first place.
It is dense in the nutrients that are hardest to get anywhere else: the long-chain omega-3s, B12, heme iron, zinc, iodine, calcium, vitamin D, choline, and the compounds like creatine and taurine that are almost absent from plants.
Being short-lived and low on the chain, it carries very little mercury, and the microplastics it eats stay in the gut, which gets removed.
It is cheap, which is its own kind of ethics: the money a tin of fish saves over supplements and specialty protein can do real good somewhere it counts.
For most people the honest alternative to beef is not a carefully supplemented plant plate. It is chicken. A sardine beats both.
Weighing it honestly
There is a real case on the other side. If you count gross suffering, with every death fully owned, the cow does win. Thousands of sardines, even at a sliver of the moral weight each, can sum past a single calf, and the same weighting that condemns chicken ranks beef as a modest harm. Someone who rejects the counterfactual frame, who holds that a death you cause is a death you cause whether or not nature would have done it anyway, can land on beef without being a fool. The pastured steer's decent life is real, and the wild sardine has nothing like it. None of that gets waved away.
The verdict
But the counterfactual frame is the right one, because the only thing your choice can change is the difference it makes. On that axis the sardine wins, and not narrowly:
it can barely suffer;
its death mostly replaces a worse one it was already going to meet;
it costs the living world almost nothing;
and it feeds you better and cheaper than the alternatives.
The cow adds a whole created life and the largest footprint on the menu. The instinct that the tin of small silver fish is the worse thing, and the one big calm animal the cleaner choice, has the arithmetic backwards. Sardines are more ethical than beef. The honest disagreement is not whether you find the fish less appetizing. It is whether you count the suffering you cause, or the suffering you actually add.